Dimensions of electrical resistance are
We know that
Ohm’s law, V = IR
[where V is Voltage, R is Resistance and I is current]
An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be
For emission, the wave number of the radiation is given as
R = Rydberg constant, z = atomic number
A boat takes 2 h to travel 8 km and back in still water, the velocity of water 4 km/h, the time taken for goir up stream 8 km and coming track is
Boats covers distance of 16 km in a still water in 2 h
i.e VB = 16/2 = 8km/h
Given, velocity of water Vw = 4 km/h.
So, time taken for upstream
Therefore, time taken for downstream
A body of mass 2 kg is rotating on a circular path of radius 0.8 m with an angular velocity 44 rac sec. If radius of path becomes 1 m then value t angular velocity will be
We shall apply conservation of angular momentum; that is
I1ω1 = I2ω2
⇒ mv1r1 = mv2r2 ⇒ ω1r12 = ω2r22
⇒ 44 x (0.8)2 = ω2 x (1)2
⇒ ω2 = 44 x 0.8 x 0.8 = 28.16 radius/sec
The string of a pendulum is horizontal. The mass of bob attached to it is m. Now, the string is released. The tension in the string in the lowest position is
According to conservation of Energy
KE = PE
So, V2 = 2gh
V2 = 2gR (∵ h = R)
Now, while it is at the bottom
T = mg + 2mg = 3mg
An observer moves towards a stationary source of sound with a speed l/5th of the speed of sound. The wavelength and frequency of the source emitted by any source be λ, and f respectively. The apparent frequency and wavelength recorded by the observer are respectively -
wavelength remains constant (unchanged) in this case.
Two similar springs P and Q have spring constants Kp and Kq , such that Kp > KQ. They are stretched, first by the same amount (case a), then by the same force (case b). The work done by the springs Wp and WQ are related as, in case (a) and case (b), respectively
In case (a)
So, Wp > WQ
Now In case (B)
So, Wp < WQ
A heater of 220 V heats a volume of water in 5 minutes. A heater of 110 V heats the same volume of water in
Heat produced, H = V2t/R. When voltage is halved, the heat produced becomes one fourth. Hence time taken to heat the water becomes four time.
In an orbital motion, the angular momentum vector is
We know that P is linear momentum of a particle and r is position vector from the point of rotation.
Now, angular momentum isL = r * p = rp sin θ when is unit vector in direction of rotation.
So, angular momentum is perpendicular to orbital plane,
The perfect gas equation for 4 gram of hydrogen gas is
n = 4/2 = 2 ∴ Pv = 2RT
A circular road of radius 1000 m has banking angle 45°. The maximum safe speed of a car having mass 200 kg will be, if the coefficient of friction between tyre and road is 0.5
Velocity of banked road with fraction
According to Einstein’s photoelectric equation, the plot of the kinetic energy of the emittec photoelectrons from a metal vs the frequency of the incident radiation gives a straight line whose slope
This is equation of a straight line, if we plot v , K -E curve. The slope of this curve is 1/h which is constant. So, it is independent of metal used.
A black body calorimeter filled with hot water cools from 60°C to 50°C in 4 min and 40°C to 30°C in 8 min. The approximate temperature of surrounding is
Given, θl =60
θ2 = 50 [where θ is the temperature of surroundings] t =4
Case II ⇒ Given
θ1 = 40
θ2 = 40
Now on solving these equations, then we get
In a nuclear fission, 0.1% mass is converted into energy. The energy released by the fission of 1 kg mass will be
0 .1 % of 1 kg = 0.001 kg
From the formula, E = mc2
= 0.001 x (3 x 108 )2 joules
= 9 x 1016x 10-3 = 9 x 1013J
The electric current in a circuit is given by I = 3t
Here, t is in second, I is in ampere. The rms current for the period t = 0 to t = 1 s is
I = 3t
I2 = 9t2
∴ Irms = √3 A
A projectile is thrown in the upward direction making an angle of 60° with the horizontal direction, with a velocity of 147 ms-1. Then the time after which inclination with the horizontal is 45°, is
At the two points of the trajectory during projectile motion, the horizontal component of the velocity is same. Then u cos 60° = v cos 45°
Pressure versus temperature graph of an ideal gas is as shown in figure. Corresponding density (p versus volume (V) graph will be
The equation of state for an adiabatic process is
PVT = constant
PVr-1 = constant
Trp1-r = constant
So, the graph will be
A tin nucleus (atomic number Z = 50) has a radius of 6.6 x 10-15 m. The potential on its surface will be (the charge on the proton = 1.6 x 10-19 C)
Charge on the tin nucleus - n.Q
= (1.6 x 10-19 x 50) C = 8 x 10-18C
This charge is supposed to be concentrated at its centre. Hence, potential on the surface,
Velocity of sound in the atmosphere of a planet is 500 ms-1. The minium distance between the source of sound and the obstacle to hear the echo should be
Total distance travelled by the Sound in going and coming back should not be more than 50 m because time taken by the reflected wave to return to the source should not be more than 0.15.
Two rods of the same length and areas of cross section A1 and A2 have their ends at the same temperature K1 and K2 are the thermal conductivities of the two rods. The rate of flow of heat is same in both rods if
The electric charge on drop B is 1.6 x l0-19C and its mass is 1.6 x 10-14 kg. If the drop is in equilibrium, then the potential difference between the plates will be (where, density d = 10 x 10-3 kgm-3)
∵ E = V/d
mg = qE
V = mgd/q
v =104 V
A cylindrical resonance tube, open at both ends has a fundamental frequency f in air, If half of the length is dipped vertically in water, the fundamental frequency of the air column will be
From the figure it is clear that in both the cases wavelength is same. So, frequency of fundamental tone will also be same. Hence the answer will be (c).
Twenty identical bulbs are connected in series across a 220 V supply. Two of the bulbs are found to bum out. The remaining 18 bulbs are connected again in series across the same supply. The illumination will be
Two of the bulbs are bum out and the 18 bulbs are remaining and all the bulbs are connected to Series the effective resistance are reduced its result higher current flow through the combinations. So illumination will be more than with 18 bulbs and with 20 bulbs
The kinetic energy of a body becomes four times its inital value. The new momentum will be
as K is made four times P will become two times.
The coefficients of self-induction of two coils are L1 ant L2. To induce an emf of 25 V in the coils change of current of 1A has to be produced in 5s and 50 ms respectively. The ratio of their self-inductances L1: L2 will be
From the formula of self inductance
so, L ∝ dt
The voltage time (V-t) graph for triangular wave having peak value V0 is as shown in figure. The rms value of V in time interval from t = 0 to T/4 is then find the value of x.
The speed of electromagnetic waves in a vacuum, is given by
By moxwell’s theory predicted that Em waves of all frequencies propagate in vacuum with a speed is given by
A 2 kg copper block is heated to 500°C and then it is placed on a large block of ice at 0°C. If the specific heat capacity of copper is 400 J/kg°C and latent heat of fusion of water is 3.5 x 105 J/kg, the amount of ice that can melt is
Let x kg of ice can melt
Using law of Calorimetry
Heat lost by copper = Heat gained by ice
2 * 400 * (500 - 0) = x * 3.5 * 105
Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are
A current of I ampere flows in a wire forming a circular are of radius r meters subtending an angle θ at the cintre as shown. The magnetic field at the centre O in tesla is
What will be the number of photons emitted per second by a 10 W sodium vapour lamp assuming that 90% of the consumed energy is converted into light? Wavelength of sodium light is 590 nm h =6.63 x 10-34 J- s.
∵ Energy of Photon E = hc/λ
Light energy Produced Per second
∴ Number of photons emitted per second
A radioactive nuclei with decay constant 0.5/s is being produced at a constant rate of 100 nuclei/s. If at t = 0 there were no nuclei, the time when there are 50 nuclei is:
Let N be the number of nuclei at any time t then,
As. N= 50 and λ = 0.5/sec
Solving we get,
Taking Rydberg’s constant RH =1.097 x 107 m first and second wavelength of Balmer series in hydrogen Spectrum, is
From the balmer series
= 1.524 x 106 m
λ1 = 6562
A uniform solid cylinderal roller of mass 'm' is being pulled on a horizontal surface with force F parallel to the surface and applied at its centre. If the acceleration of the cylinder is 'a' and it is rolling without slipping then the value of 'F' is:
ma = F - f .. (1)
Mass = m
And, torque τ = Iα
Put this value in equation (i),
The total energy of an electron in the first excited state of hydrogen is about -3.4 eV, Its kinetic energy in this state is
Kinetic energy of electron
Total energy = K + U
K = -E
= - ( -3.4) = 3.4 ev
Figure shows three oscillating LC Circuit with identical inductors and capacitors. If t1, t2, t3 are the time taken by the circuits I, II, III for fully discharge, then
clearly t2 < t1 < t3
The unit of thermal conductivity is
Dimensional formula of thermal conductivity is
So, the unit is k s-1
A spherical ball of iron of radius 2 mm is falling through a column of glycerine and iron are respectively 1.3 x 103 kg/m3 and 8 x 103 kg/m3, η for glycerine - 0.83 Nm-2 sec, then the terminal velocity is
A sound source is moving towards stationary listener with 1/10th of the speed of sound. The ratio of apparent to real frequency is
apparent to the real frequency is
Now, Substituting Vs = 1/10 c
then we get
Surface tension of a solution is 30 x 10-2 N/m. The radius of the soap bubble is 5 cm. The surface energy of soap bubble is
Surface tension of solution
(T) = 30 x 10 -12 N / m
Radius of the soap bubble (r) = 5 cm = 0.05 m
Since, the bubble has two spherical surface
hence, ΔA = 2 x surface area - 2 x 4 πr2
Therefore, surface energy =T x ΔA
=30 x 10-2 x 2 x [4 π (0.05)2]
= 1.8 x 10-2 J
Two nicol prisms are placed with their principal planes at 60°. What percentage of light incident on the combination is transmitted
In household electric circuit, which of the following statements is/are incorrect
What determines the nature of the path followed by the particle ?
Velocity and acceleration determines the nature of the path followed by the particle.
An intersteller spacecraft far away from the influence of any star or planet is moving at high speed under the influence of fusion rockets (due to thrust exerted by fusion rockets, the spacecrafts is accelearting). Suddenly the engine malfunctions and stops. The spacecraft will
Due to malfunctioning of engine, the process of rocket fusion stops hence net force experienced by the spacecraft becomes zero. Afterwards the spacecraft continues to move with a constant speed.
A ray of light travelling in a transparent medium of refractive index μ falls, on a surface separating the medium from air at an angle of incidence of 45°. For which of the following value of μ the ray can undergo total internal reflection?
For total intemnal reflection (TIR)
μ = √2
So, μ = 1.40
Which one of the following sets of compounds correctly illustrates the law of reciprocal proportions?
similarly, check for other cases
A is a lighter phenol and B is an aromatic carboxylic acid. Separation of a mixture of A and B can be carried out easily by using a solution of :
Carboxylic acids dissolve in NaHCO3 but phenols do not.
A standing wave in a string 35 cm long has a total of six nodes including those at the ends Hence, wavelength of the standing wave is
Which of the following is not correct ?
The correct reaction is
The statement that is not correct for periodic classification of elements is
In principle, electrons are added one at a time to the penultimate d-orbitals but due to extra stability of d5 and d10 configurations two electrons appear to have entered the d-shell due to shifting of one electron from ns to (n - 1)d orbital.
Which of the following compounds is a good conductor of electricity in solution state?
Ionic compounds are dissociated in solution state and form ions. Ions are good carrier of charge. So it makes solution conducting.
The ONO bond angle is maximum in
NO3- has sp2 hybridisation and three resonating
Hence, ONO bond angle = 120°
NO2+ has no unshared electron. It has only bond pairs in two directions. Hence, shape is linear
with bond angle = 180° NO2 has one unshared electron whereas NO2-, has one unshared electron pair. Hence, in NO2-, the repulsion on the bond pairs are more and angle in less
N2 + 3H2 → 2NH3. In this reaction equivalent weight of N2 is
Thus, equivalent weight of N2
A bubble of a gas released at the bottom of a lake increases to eight times its original volume when it reaches the surface. Assuming that atmospheric pressure is equivalent to the pressure exerted by a column!of water 10 m height, the depth of the lake is
A volume of the bubble at the surface becomes 8 times, pressure at the bottom of the lake is 8 times the pressure at the surface.
As pressure on the surface = 1 atm, pressure at the bottom = 8 atm
Thus, pressure due to depth of the lake = 7 atm = 70m of water
Zn2+ → Zn (s); E0 = -0.76 V
Cu2+ → Cu (s); E0 = - 0.34
Which of the following is spontaneous?
For spontaneous reaction E0cell must be positive.
Here Cu acts as cathode and zinc acts as anode.
The difference in the work done when one mole of Al4C3 (s) reacts with water in a closed vessel at 27°C against; atmospheric pressure and that in an open vessel under the same conditions is
Reaction occuring is
When the vessel is closed, volume = constant i.e.,
ΔV = 0
Hence, W = -PΔV = 0
When vessel is open, initial volume,
V1 = 0 (as no gas is present)
Final volume, V2 = volume of 3 mole of CH4
PV2 = nRT
∴ W = -P (V2 - V1)
i.e., work is done by the system.
Consider the following fee unit cells and choose the correct option.
Examine the nearest number of neighbours in (I) and (II). The number is six which is octahedral
For the synthesis of ammonia by the reaction in the Haber’s process, the attainment of equilibrium is correcdy predicted by the curve.
(a) is correct because concentrations of H2 and N2 decrease with time while that of NH3 increases with time and after equilibrium, all of them remain constant.
At a particular temperature, the vapour pressures of two liquids A and B are respectively 120 and 180 mm of mercury. If 2 moles of A and 3 moles of B are mixed to form an ideal solution, the vapour pressure of the solution at the same temperature will be (in mm of mercury)
Vapour pressure of solution,
Equimolar solutions of the following were prepared in water separately, which one of the solutions will record the highest pH?
All alkaline earth metal chlorides (MCl2) on hydrolysis will produce acidic solution because the base formed, M(OH)2 is weak and acid formed (HCI) is strong. However, as we go down the group, basic character of hydroxides increases. Hence, acidic character decreases, i.e. pH increases (though it is < 7 in all cases). Therefore, BaCl2 solution will have the highest pH.
According to the adsorption theory of catalysis, the speed of the reaction increases because
According to the adsorption theory of catalysis, the activity of catalysis is due to the presence of free valencies on its surface due to which surface of catalyst has chemical force of attraction. When a gas comes in contact with this surface molecules get attached through these valencies. Further the rate of reaction is always increases by decreases in activation energy When any of the reactants is strongly adsorbed on the surface of catalyst, the rate becomes inversely proportional to the concentration of that reaction. The reaction is then said to be inhibited by such reactant. The lowering of activation energy always leads to the increase in speed of reaction.
If a half cell, A + e- → A- has a large negative potential, it follows that
Large negative potential for the reaction A + e- → A- implies that the reverse reaction occurs, i.e., A- is readily oxidised.
Most reactive halide towards SN1 reaction is
More stable the carbocation, more reactive will be the parent alkyl halide towards SN1 reaction.
3° > Benzyl > Allyl > 2° > 1° > methyl
The correct order of reducing character of alkali metals is
Li has the most negative E° value while E° values of other alkali metals become more and more negative as we move down the group from Na to Rb. Thus, option (c) is correct.
The rate constant k, for the reaction
is 1.3 x 10-2s-3. Which equation given below describes the change of [N2O5] with time ? [N2O5]0 and [N2O5]t correspond to concentration of N2O5 initially and at time t.
As the unit of rate constant is sec-1, so the reaction is first order reaction. Hence
Which of the following is not a monomer for a high molecular mass silicone polymer?
Me3 SiCl on hydrolysis gives Me3SiOHwhich has only one OH group and hence cannot act as a monomer in condensation polymerization to give high molecular mass silicone polymer.
Lead is not affected by dil. HCl in cold because
Pb with dil HCl forms protective coating of PbCl2
A gaseous hydrocarbons gives upon combustible 0.72 g of water and 3.08 g of CO2. The empirical formula of the hydrocarbon is
Let the mass of gaseous hydrocarbon taken = w gm
Thus, empercial formula = C7H8
X is identified as
When we have groups with +M and -M effect on the ring, then the position of substitution is decided by the group with +M effect.
Considering this fact, we have 2 ortho positions wrt OH for substitution.
So the compound formed is 3,5-dibromo-4-hydroxybenzenesulfonic acid.
Reaction of benzene with Me3CCOCl in the presence of anhydrous AlCl3 gives
The initially formed acylium ion (I) readily eliminates a stable molecule of CO to form tert-butyl Carbocation which then attacks the benzene ring to form tert-butyl benzene.
Aluminium displaces hydrogen from acids but copper does not. A galvanic cell prepared by combining Cu/Cu2+ and Al/Al3+ has an e.m.f of 2.0 V at 298 K. If the potential of copper electrode is + 0.34 V, that of aluminium is
The given statement explains that Al is placed above Cu in E.C.S. hence it can reduce Cu from its salt solution (reduction).
Thus Al acts as a reducing agent now,
Given : electrode potential of copper
(E0cell) = + 0.34 V
e.m.fofcell = 2V
We know that,
emf of a galvanic cell (E0cell) = electrode potential of Cu (cathode) - electrode potential of Al (anode)
2.0 = 0.34 - E0Al
E0Al = 0.34 - 2.00 = -1.66 V
Hence, electrode potential of Al is - 1.66 V.
Option (b) is correct.
If the unit cell of a mineral has a cubic close packed (CCP) array of oxygen atoms with m fraction of octahedral holes occupied by aluminum ions and n fraction of tetrahedral holes occupied by magnesium ions, m and n, respectively are
In ccp lattice, z = 4
∴ No. of O-atoms per unit cell = 4 (O2-) ∴ No. of octahedral voids = 4
and No. of tetrahedral Voids = 8.
As m fraction of octahedral voids is occupied by Al3+ ions therefore Al3+ ions present = 4 m.
Similarly Mg2+ ions = 8n. Hence, formula of the mineral is Al4n Mg8n O4.
As total charge on the compound is zero.
Hence 4m(+3) + 8n(+2) + 4 (-2) = 0
or 12m + 16 n - 8 = 0
Substituting the given values of m and n, equation is satisfied only when
A sudden large jumps between the values of second and third ionization energies of an element, would be associated with which of the following electronic configuration?
On losing two electrons from 1s2 2s2 2p6 3s2 electronic configuration, becomes 1s2 2s2 2p6 3s0, it is m ore stable than 1s2 2s2 2p6 3s2. Therefore, the difference in values of Ilnd ionisation energy and IIIrd ionisation energy of this configuration is more.
Hence, option (c) is correct
At a certain temperature, the value of the slope of the plot of osmotic pressure (π) against concentration (in mol L-1) of a certain polymer solution is 219 R. The temperature at which osmotic pressure is measured is (R is gas constant)
π = CRT. Thus, a plot of π Vs C will be linear with slope = RT. Hence,
RT = 291 R or T = 291
K = (291 - 273)°C
On increasing the pressure, the gas phase reaction proceed forward to re-establish equilibrium, as predicted by applying the Le-Chatelier’s principle. Consider the reaction.
Which of the following is correct, if the total pressure at which the equilibrium is established, is increased without changing the temperature?
Justification : According to Le-Chatelier’s principle, at constant temperature, the equilibrium composition will change but K will remain same.
Electrolysis of dilute aqueous NaCl solution w as carried out by passing 10 milli ampere current. The time required to liberate 0.01 mol of H2 gas at the cathode is (1 Faraday = 96500 mol- 1)
NaCl +aq → Na+ + Cl-
Thus, 0.5 mole of H2 is liberated by IF = 96500 C
∴ 0.01 mole of H2 will be liberated by charge
The oxidation states of iodine in HIO4, H3IO5 and H5IO6 are respectively
Calculating the oxidation states of I, we get
H5IO6 ; 5 + x - 12 = 0 or x = +7
H3lO5 ; 3 + x - 10 = 0 or x = +7
HIO4 ; 1 + x - 8 = 0 or x = +7
Thus, the correct answer is +7, +7, +7
For a second order reaction, 2 A → Products a plot of log t1/2 vs log a (Where a is the initial concentration) will give an intercept equal to which of the following ?
For a second order reaction,
2A → Products,
∴ log t1/2 = - log k - log [A]0
= -log k - log a
plot of log t1/2 Vs log a will be linear with intercept = log k
Regarding F- and Cl- which of the following statements is/are correct?
(i) Cl- can give up an electron more easily than F-.
(ii) Cl- is a better reducing agent than I-.
(iii) Cl- is smaller in size than F-.
(iv) F- can be oxidized more readily than Cl-.
The halide ions act as reducing agents. F- ion does not show' any reducing nature but Cl- , Br- & I- ion act as reducing agents and their reducing nature is in increasing order
Tanning of leather is
Tannin obtained from plants contains negatively charged colloidal particles. Animal hides contain positively charged particles. When they are socked in tannin, mutual coagulation takes and leather becomes hard.
Carbon and silicon belong to group 14. The maximum coordination number of carbon in commonly occurring compounds is 4, whereas that of silicon is 6. This is due to
Due to non-availability of vacant d- orbitals, it cannot exceed its coordination number more than four. Thus carbon never forms complexes e.g., [CCl6]2- deos not exist but [SiCl6]2- exists.
Copper is extracted from copper pyrites by heating in a Bessemer converter. The method is based on the principle that
When copper pyrites is heated in a bessemer converter in presence of a blast of oxygen. It is initially converted into a mixture of CV2S, FeS and SO2.
2CuFeS2 + O2 → Cu2S + 2FeS + SO2 Since Cu2O is not formed initially even in the presence of O2, therefore copper has less affinity for oxygen than sulphur at high temperature, i.e., option (d) is correct.
Among the following molecules
Those having same number of lone pairs on Xe are
Thus, all the three have same no. of lone pair of electrons i.e. one.
Reason of lanthanoid contraction is
Due to poor screening or shielding effect of 4 orbitals, nucleus will exert a stronger attraction and size of atom or ion goes on decreasing as we move in the series with increase in atomic number.
Which of the following is not a fat soluble vitamin?
Vitamin B complex is water soluble vitamin whereas vitamin A, D, E and K are fat soluble vitamin.
The major product formed in the following reaction is
Since CH3O- is a strong nucleophile as will as a strong base, therefore, it can either bring about substitution or elimination. Now, the CH3 group at β-Carbon causes steric hinderance to nucleophilic Substitution (SN2), th e refore, elim ination ( E2) occurs preferentially, to form 2-methyl propene.
[Cr(H2O6)]Cl3 (At no. of Cr = 24) has a magnetic moment of 3.83 B. M. The correct distribution of 3d electrons in the Chromium metal of the complex is
on solving n = 3
as per magnetic moment, it has three unpaired electron.
Cr3+ will have configuration as
A compound of molecular formula C5H10O(A) reacts with Tollen’s reagent to give silver mirror but does not undergo aldol condensation. The compound A is
Since the compound (A) with M.F C5H10 Oreacts with Tollen’s reagent to give silver mirror, it must be an aldehyde. Since it does not undergo aldol condensation, it does not contain a-hydrogen (s). Thus, the aldehyde is 2,2 - dimethyl propanal, i.e., option (b) is correct.
The correct statements among (A) to (D) are
(A) Saline hydrides produce H2 gas when reacted with H2O.
(B) Reaction of LiAlH4 with BF3 leads to B2H6.
(C) PH3 and CH4 are electron rich and electron precise hydrides, respectively.
(D) HCl and CH4 are called as molecular hydrides.
(A) Saline hydrides with water produces H2 gas.
(B) 3LiAlH4 + 4BF3 → 2B2H6 + 3LiF + 3AIF3
(C) PH3 is electron rich whereas CH4 is electron precise hydride.
(D) HCl and CH4 are molecular hydrides.
The correct structure of the dipeptide gly-ala is
Thus, pption (c) is correct.
Which step is required for better survival of human being?
For better survival of life, human being should reduced utilisation of resources.
A water fern which is used as a green manure in rice fields is
Azolla has been used as a green manure crop in Vietnam and China for centuries. The ability of Azolla to shade out weeds in wetland rice and taro has been noted by farmers and researchers since the early 20th century.
The sclerenchyma of the hypodermis in the pinus needle helps in one of the following function
The Sclerenchyma of the hypodermis in the pinus needle helps in mechanical support like ion-exchange and loss of water.
Conifers are especially sensitive to acid rain because their needles literally take moisture out of clouds. Because of acid rain, Mt. Mitchell, the highest peak in the eastern Appalachians, has seen dramatic loss of pine forest. The damage on this mountain most likely stems from
Excess sulphur is a primary cause of acid ram.
'Taxon' is the unit of a group of
Taxon may be defined as the taxonomic group
Which of the following pairs are haploid structures?
Nucellus - 2n, antipodal cells - n
Antipodal cells - n, egg cell - n
Antipodal cells - n, megaspore mother cell-2n
Nucellus - 2n, primary endosperm nucleus - 3n
Antipodal and egg cell are the product of meiotic division and rest are not.
Nucellar polyembryony is reported in species of
It is a type of seed formation in which the nucellar cells that are present in the embryo divide and form many more embryos. These are the exact clones of the parents because these are formed from nucellar cells.
Nuclear polyembryony is seen in the members of the citrus family.
So, the correct option is 'Citrus'.
Acacia trees endure a 7-month dry season in the African savanna by dropping their leaves. This adaptation allows the trees to
Without leaves there can be no evaporation from the leaf surfaces, greatly reducing water loss.
A gene showing codominance has
Codominance is when alleles show a codominant relationship and both alleles independently expressed in the heterozygote.
Six tubes containing preparations from animal tissue were set up as shown below. Tube contents
(i) glucose + homogenised cells
(ii) glucose + mitochondria
(iii) glucose + cytoplasm lacking organelles
(iv) pyruvic acid + homogenised cells
(v) pyruvic acid + mitochondria
(vi) pyruvic acid + cytoplasm lacking organelles
After incubation, in which three tubes would carbon dioxide be produced?
Glucose and pyruvic acid serve as sources of substrates which the homogenised cells can oxidise in glycolysis and Kreb's cycle respectively. Mitochondria however, can only oxidise pyruvic acid via the Kreb's cycle.
Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called
Geitonogamy is a type of self-pollination. Such as transfer of pollen grain from the anther to the stigma of another flower of the same plant.
Reverse transcriptase is
The phenomenon of making DNA over RNA genome through enzyme reverse transcriptase is called reverse transcription or teminism.
The genetic defect-adenosine deaminase (ADA) deficiency may be cured permanently by
Adenosine deaminase deficiency also called ADA deficiency can be cured permanently by the introducing bone marrow cells into cells at early embryonic stage.
A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
(i) Lots of urea and phosphate fertiliser were used in the crops in the vicinity.
(ii) The area was sprayed with DDT by an aircraft.
(iii) The lake water turned green and stinky.
(iv) Phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis.
Lots of urea and phosphate fertilisers were used in the crops in the vicinity and the lake water turned green and stinky. Due to this, lake near a village suffered heavy mortality of fishes within a few days.
Which one of the following statements is correct?
Chemical fertilisers may lead to eutrophication of near by water bodies.
Glycogen is a polymer of :
Glycogen is an animal starch, stored in the liver and is polysaccharide of Glucose. About 30,000 glucose molecules joined by 1,4 α- glycosidic bonds and its branches by 1,6 α- glycosidic bonds. It gives red colour with iodine solution.
Which one of is a neem product used as insect repellant?
Azadirachtin, a complex tetranortri-terpenoid limonoid obtained from the neem seed it is responsible for insect repellant.
In humans, the hormone testosterone enters cells and binds to specific proteins, which in turn bind to specific sites on the cell's DNA. These proteins probably act to
The presence of testosterone enables RNA polymerase to transcribe certain specific genes.
After ovulation, Graafian follicle forms
After Ovulation, Graafian follicle forms corpus luteum i.e. a temporary endocrine structure in female ovaries
Biodiversity of a geographical region represents
Biodiversity is the number of variety of organisms found within a specified geographic region.
An aggregate fruit is one which develops from
An aggregate fruit or etaerio is a fruit that develops from the merger of several ovaries (multi carpellary apocarpous gynoecium)
A garose extracted from sea weeds finds use in :
In gel electrophoresis, agarose extracted from seaweed used as gel agarose, made of 0.7% gel show good resolution of large DNA and 2% gel will show good resolution of small fragments.
Asiatic lion is protected in
Asiatic lion is protected in Gir National park that located at Junagadh (Gujarat).
Which organelle is surrounded by a double phospholipid bilayer with many large pores?
The pores in the nuclear membrane permit large molecules such as proteins and RNA to enter or exit this organelle.
Match the following columns
The Okazaki fragments in DNA chain growth
Replication always occur in 5' - 3' direction, Okazaki fragments synthesised on 3' - 5' DNA template, join to form lagging strand which grows in 5 ' - 3' direction. These fragm ents in DNA are linkedup by the enzyme DNA ligase.
A scientist disrupted the chloroplast and separated the stroma from lamella. For fixing CO2 he supplied stroma with
Select the correct option
For CO2 fixation ATP molecules and NADPH carried with stroma in lamellae disruption.
The combination of a true coelom and repeating body segmentation allows the annelids to do which of the following that anatomically “simpler” worms cannot ?
Annelids have successfully combined true coelomic cavities, and repeating segmentation to m ore precisely control body m ovem ents compared with the anatomically simpler worms.
Passive absorption of mineral salt is not
Diffusion is not a passive absorption of mineral salt, it involves in the movement of particles not in absorption.
Excretory organs of cockroach are:
The concept of totipotency was given by
Totipotency refers to developmental flexibility. Steward gave the concept of totipotency by the experiment of regeneration.
Tendons and ligaments are the examples of:
A lake with an inflow of domestic sewage rich in organic waste may result in
Increased organic waste in domestic sewage leads to the death of fish due the anaerobic cond ition or lacking of oxygen.
Match column-I with column-II and select the correct option from the codes given below.
Cambium is the example of which of the following types apical of meristem?
Cambium are the example of dedifferentiation lateral meristem is a type of apical of meristem.
The logistic population growth is expressed by the equation:
The logistic population growth is expressed by the equation where N is population density at time t, r is the Malthusian parameter (rate of maximum population growth) and K is the so called carrying capacity (i. e. maximum sustainable population). It is a type of population growth when resources are limiting,
Identify the correct chronological sequence periods of Palaeozoic and Mesozoic era
Chronological sequence periods of palaeozoic and Mesozoic era is Caboniferous → Permian → Triassic → Jurassic → Cretaceous
Proximal and distal convoluted tubules are parts of
Nephron is the excretory unit of human excretory system. Each nephron has a Bowman’s Capsule, a Proximal Convoluted Tubule (PCT), Loop of Henle (Descending and Ascending limbs) and Distal Convoluted Tubule (DCT) which then enter into collecting duct.
Neck canal cell is absent in the archegonium of
Neck canal cells are found in the Archeogonium of fern and absent in the Archegonium of cycas.
Deposition of uric acid crystals within the synovial joint causes:
In gout, there occurs a defect in uric acid metabolism resulting into its elevated level in blood (hyperuricemia). This is followed by precipitation of excessive uric acid which gets deposited in the joint spaces. These deposited crystals of uric acid causes pain in different bony joints.
A small aquatic herb in which a portion of leaf forms a tiny sac or bladder which traps water insects is
Utricularia Vulgaris is an aquatic species of bladderwort, it is also a largest genus of carnivorous plants which trap water insects.
Match column-I with column-II and select the correct answer using the codes given below.
Taxon is a taxonomic group of any rank. Species, the lowest category in the taxonomic hierarchy, is the basic unit of taxonomy. It is the group of individual organisms with fundamental similarities. Division is similar tophylum and used in case of plants. Genus is a group of related species having more character in common with other species. Order is identified based on a number of similar characters
Withdrawal of which of the following hormones is the immediate cause of menstruation?
FSH-RH hormones cause immediate cause of menstruation in other words both RH and FSH hormone attain maximum level of menstruation.
The ovules of gymnosperms are:
Which of the following is not correct about viruses?
Outer covering of viruses is made up of proteins called capsid i.e. Made up of small subunits known as capsomers.
Following are given parts of small and large intestine.
Choose the arrangement that lists the structures in the order food passes through them from the small intestine to the anus.
The small intestine is the largest, narrow and tubular part of alimentary canal. It is divided into three parts - proximal duodenum, middle jejunum and distal ileum. Large intestine is divided into caecum, colon and rectum. The correct arrangement of the parts through which food passes from the small intestine to the anus is: Duodenum → Jejunum Ileum → Caecum → Colon → Rectum
Two plants can be conclusively said to belong to the same species if they
Two plants can be conclusively said to belong to the same species if they can reproduce freely with each other and form seeds.
Which of the following combination is incorrect?
Elaioplasts are colourless plastids which store lipids. Chromoplasts are yellow or reddish in colour because of the presence of carotenoid pigments. Chloroplasts are the most common type of plastids and are of prime biological importance as they contain chlorophyll and provide food to all organisms through photosynthesis.
In a woody dicotyledonous tree, which of the following parts will mainly consist of primary tissues?
In a woody dicotyledonous tree, shoot tips and root tips parts are mainly consists of primary tissues.
The use of Cannabis products (bhang, ganja, charas, marijuana or hashish) causes
Hallucinogens (Cannabis products) alter thoughts, perceptions and feelings. Tranquilisers bring about depression of brain activity and feeling of calmness. Stimulants stimulate the nervous system, and increase alertness and activity.
Which of the following is produced during water stress and causes closure of stomata?
Abscisic Acid (ABA) acts as a general plant growth inhibitor, inhibits seed germination, stimulates the closure of stomata, and produced during water stress.
Match column-I with column-II and select the correct option from the codes given below.
ANF (atrial natriuretic factor) hormone is released by heart, involved in decreasing of blood pressure.
MSH (Melanocyte stimulating hormone) involved in pigmentation of skin. When present in excess, can cause darkening of skin.
GIP (gastric inhibitory peptide) inhibits gastric secretion and motility.
CT (calcitonin) produced by thyroid gland, involved in regulating calcium and phosphate level in blood.
Conifers differ from grasses in the
Conifers form endosperm before fertilisation while grasses do not form endosperm before fertilisation.
Atropine is a drug that causes relaxation of the smooth muscle of the digestive tract, a dry mouth sensation, and dilated pupils. Therefore, atropine is a(n)____drug and mimics the effect of the ____nervous system.
A drug that causes inhibition of peristaltic movement of the digestive tract, a dry mouth feeling, and dilation of the pupils mimics the effects of the sympathetic division of the ANS. Thus, its effects are similar to those caused by release of norepinephrine (noradrenaline) from sympathetic postganglionic fibers.
Moss peat is used as a packing material for sending flowers and live plants to distant places because
Moss peat is decayed dried sphagnum moss. It is hygroscopic, ie. it has the ability to hold water either by absorption or adsorption thats why it is used as packing material.
What is true about T-lymphocytes in mammals?
The T-lymphocytes originate in hematopoietic stem cells in the bone marrow and mature in the thymus. T-lymphocytes are responsible for humoral immunity. There are different types of T cells. They are listed below:
a. T- helper cells which assist other WBCs in the immunologic process.
b. Cytotoxic T-cells destroy virus-infected cells and tumor cells.
c. Suppressor T-cells are crucial for the maintenance of immunological tolerance.
d. Memory T-cells which persist in the blood for future infections
Which one of the following statements about mycoplasma is wrong?
Mycoplasma also called as PPLO, they are pleomorphic and cause disease in various plants and animals. Not sensitive to antibiotics.
Jurassic period of the mesozoic era was characterised by:
Jurassic period of meoszoic era was about 19-20 crore years ago and lasted for about 5.5-6 crore years. The climate was hot and damp. It is called the age of dinosaurs. 1st primitive bird Archaeopteryx evolved from reptiles. 1st angiosperm appeared as dicotyledons but gymnosperms were dominant.
One of the representative of phylum-Arthropoda is
Thysanura (order) i.e. Lepisma (Silver fish) is an exam ple o f the phylum-Arthropoda.
In history of biology, human genome project led to the development of :
Common activities in bioinformatics include mapping and analysing DNA and protein sequencing, aligning different DNA etc. are the part of human genome project.
Many care painting have been discovered in recent centuries. One of the following fossil man believed to make these painting is
Cro-magnon man believed to make care paintings.
Angiotensinogen is a protein produced and secreted by:
CAM helps the plants in
CAM (Crassulacean Acid Metabolism) is an alternative of C3 and C4 path way of CO2 fixation. This pathw ay helps in the conserving water in the plants.
In a seed of maize, scutellum is considered as cotyledon because it:
In the embryos of a typical dicot and a grass, true homologous structures are:
The ratio between 2-carbon and 3-carbon intermediates having — NH2 group formed in photosynthetic Oxidation cycle is
In Photosynthetic oxidation cycle, 2-carbon atoms adjoined with 1-NH2 group then the ratio is 2 :1
Blastopore is the opening to the exterior of
Blastopore is the opening to the exterior of coelenteron anus or mouth.
Which of the following food chain produces a greater availability of food to next trophic level?
Shorter the food chain, more is the availability of food to consumer.
Patients suffering from cholera are given a saline drip because
Cholera is an infectious disease that causes severe watery diarrhea which can lead to dehydration that is why should be given a saline drip to the patient because Na+ help in the retention of water in the body tissues.
DNA has alternate grooves:
During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has which type of electric charge?