In an A.C. circuit containing an inductance only, the current
Photo electric emission is observed from a metallic surface for frequencies ν1 and ν2 of the incident light rays ν1 > ν2. If the maximum values of kinetic energy of the photo electrons emitted in the two cases are in the ration of 1 : K then the threshold frequency of the metallic surface is
In uniform circular motion
A steady current ι is flowing through a conductor of uniform cross-section. Any segment of the conductor has
A wire of resistance R is cut into 'n' equal parts. These parts are then connected in parallel. The equivalent resistance of the combination will be
A transformer is used to reduce the mains supply of 220 V to 11 V. If the currents in primary and secondary coils are 5 A and 90 A respectively, efficiency of transformer is
Two condensers, one of capacity C and the other of capacity C/2 , are connected to a V volt battery, as shown.
The work done in charging fully both the condensers is
The power factor of an a.c. circuit having resistance R and inductance L connected in series to an a.c. source of angular frequency ω is
Which is having minimum wavelength:
Three charges, each equal to +q, are placed at the corners of an equilateral triangle. If the force between any two charges is F, then net force on either charge will be
A work of 100 J is done in moving a charge of -5C from infinity to a particular point in an electrostatic field. The potential of this point is
Newton's law of cooling, holds good only if the temperature difference between the body and the surroundings is
A satellite revolves around the earth in an elliptical orbit. Its speed
Out of following, the only correct statement about satellites is
The coefficient of friction between a body and the surface of an inclined plane at 45º is 0.5. If g=9.8 m/s2, the acceleration of the body downwards in m/s2 is
Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is π/2 at point A and π at point B. Then the differnce between the resultant intensities at A and B is
The average kinetic energy of a gas molecules at 27ºC is 6.3×10⁻²¹J. Its average kinetic energy at 227ºC will be
The magnetic field d̅B due to a small current element dl at a distance r and element carrying current i is
Magnetic field induction at one end on the axis of a long solenoid having n turns per unit lengh and carrying i ampere current is
A bar magnet is oscillating in earth's magnetic field with a period T. What happens to its period of motion, if its mass is quadrupled ?
A potential difference of 2V exists across a potentiometer wire of 2m length. When the potential difference across a 2Ω resistance of a second circuit is measured by this potentiometer wire, it amounts to 5mm balancing length. The current in the second circuit is
Potential gradient in the wire
= 2 2 = 1V/m
P.D. across a balancing length of 5 mm
= 5 x 10-3 x 1
= 5 x 10-3 V
∴ Current in the second circuit
= 5 x 10 − 3 2 = 2.5 x 10-3 A
= 25 x 10-4 A
The unit of magnetic permeability is
A magnetic needle suspended freely orients itself
A body floats in a liquid contained in a beaker. If the whole system falls under gravity, then the upthrust on the body due to liquid is
A column of water 60 cm high supports a column of an unknown liquid of density 1500 kg-m⁻3. The height of liquid column is (Density of water = 1000 kg-m⁻3)
A cube is subjected to a uniform volumatric compression. If side of cube decreases by 1%, then its bulk strain is
Moment of inertia of a uniform circular disc about a diameter is I. Its moment of inertia about an axis perpendicular to its plane and passing through a point on its rim will be
Acceleration of a particle changes when
The number of neutrons in a chain reaction increases in
What is the Q-value of the reaction
p + 7Li → 4He + 4He
The atomic masses of 1H , 4He and 7Li are 1.007825 u, 4.002603 u and 7.016004 u respectively
A 2 kg block is lying on a smooth table which is connected by a body of mass 1 kg by a string which passes through a pulley. The 1 kg mass is hanging vertically. The acceleration of block and tension in the string will be
A simple pendulum of length l has a bob of mass m, with a charge q on it. A vertical sheet of charge, with surface charge density σ passes through the point of suspension. At equilibrium, the spring makes an angle θ with the vertical. its time period oscillations is T in this poisiton. Then
All of the following statements are correct except
Sodium and copper have work functions 2.3 eV and 4.5 eV respectively. Then the ratio of the threshold wavelengths is nearest to
If in a photoelectric experiment, the wavelength of incident radiation is reduced from 6000Å to 4000Å, then
A ball is thrown upwards and it returns to ground describing a parabolic path. Which of the following remains constant
A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a
A ray of light is incident at 60º on a prism of refracting angle 30º . The emergent ray is at an angle 30º with the incident ray. The value of refractive index of the prism is
Angle of prism = 30º = A
Angle of incidence = i1 = 60º
Angle of emergence = i2 = ?
Angle of devation = D = 30º
∴ i2 = A + D - i2 = 30 + 30 - 60 = 0º
⇒ r2 = 0º
The solar system is an example of
Two lenses of focal lengths 75 cm and 25 cm, will form a combination satisfying the conditions for no chromatic aberration and minimum spherical aberration, when they are placed with a distance of separation .....cm.
One face of a rectangular glass plate 6 cm thick is silvered. An object held 8 cm in front of first face, forms an image 12 cm behind the silvered face. The refractive index of the glass is
Let the apparent position of the silvered surface = x cm.
Since the image is formed due to the reflection at the silvered face and also according to property of plane mirror
Distance of object from the mirror = Distance of image from the mirror
∴ x + 8 = 12 + 6 - x
or 2x = 18 - 8 = 10
or x = 5
Now refractive index μ
A particle is executing simple harmonic motion with an amplitude of 4cm. At the mean position, the velocity of the particle is 10 cms−1 . The distance of the particle from the mean position when its speed becomes 5cms−1 is
To a germanium sample, traces of gallium are added as an impurity. The resultant sample would behave like
A seconds pendulum is taken from earth to moon. If it is to act as a seconds pendulum there also, the length of the pendulum,
On increasing the reverse bias to a large value in a P-N junction diode current
An observer is moving away from a source of sound of frequency 100 Hz. His speed is 33 ms-1. If speed of sound is 330 ms-1, the observed frequency is
If σ be the surface tension, the work done in breaking a big drop of radius R in n drops of equal radius is
For electroplating a spoon, it is placed in the voltameter at
There are two electric bulbs of 40 W and 100 W. Which one will be brigther when first connected in series and then in parallel
A heater of 220 V haets a volume of water in 5 minute time. A heater of 110 V haets the same volume of water in
A closed copper vessel contains water equal to half of its volume. When the temperature of the vessel is raised to 447º C, the pressure of the steam in the vessel is (treat steam as an ideal gas, R = 8310JK-1/ mole, density of water =1000 kg m-3, molecular weight of water = 18)
A sample of gas expands from volume V₁ to V₂. The amount of work done by the gas is greatest when the expansion is
What is most affected, when copper cube is heated?
One yard in SI unit is equal to
Dimensions of 'ohm' are same as (where h is Planck's constant and e is charge)
X-rays are diffracted from a crystal of lattice plane spacing 2 Å . The maximum wavelength that can be diffracted is
Two sources of same intensity interfere at a point and produced resultant I. When one source is removed, the intensity at that point will be
Quality of sound depends upon
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine . The losses due to frictional forces are 10% of energy . How much power is generated by the turbine ?(g = 10 m/s2)
A cylindrical tube open at both the ends has a fundamental frequency of 390Hz in air. If 1/4th of the tube is immersed vertically in water the fundamental frequency of air column is
Conc. HNO3 forms NO2 + in presence of :
When acetylene gas is passed through solution, a white precipitate is formed
CH₃-CH=CH₂+HI → X. here X is
In its reaction with silver nitrate acetylene shows
The energy of second Bohr orbit of the hydrogen atom is -328KJ mol⁻1. The energy of fourth Bohr orbit would be
Which of the following does not react with AgCl?
Which of the following is not isoelectronic?
Which of the following sets of quantum numbers is correct for an electron in 4f-orbitals?
In the process of nitration, the electrophile formed is
Which of the following phenomenon will occur when two atoms of the elements having same spin of electron approach for bonding?
The maximum number of hydrogen bonds formed by a water molecule in ice, is
The enthalpies of formation of Al₂O and Cr₂O₃ are- 1596 KJ and -1134 KJ respectively. The value of ∆H for the reaction of 2Al + Cr₂O₃ → 2Cr + Al₂O₃ is
For the reaction N2O4 ⇌ 2NO2 Kp = 640 mm at 775 K. At equilibrium pressure of 160 mm, the degree of dissociation is
Given the bond energies of N ≡ N , H − H and N − H bonds as 941.5, 433 and 391 kJ mole-1 respectively, the enthalpy of reaction N2(g) + 3H2(g) → 2NH3(g) is
Enthalpy of reaction = ∑ bond energyreactant - ∑ bond energyproduct
= bond energy (n2) + 3 x (bond energy) (h2) - 2 x (bond energy) (NH3)
= 941.5 + (3 x 433) - 2 x 3 x 391
= 2240.5 - 2346 = 105.4 ≅ -105kJ
A catalyst is used to
A solution of 500ml of 2M Postassium hydroxide is added to 500ml of 2M hydrochloric acid and mixture is well stirred. The rise in temperature 'T1' is recorded. The experiment is then repeated using 250ml of each solution and the rise in temperature 'T' is recorded. Then which of the following statement will be correct?
Which of the following statement about fluorine is not correct?
Industrial production of fluorine entails the electrolysis of hydrogen fluoride in the presence of potassium fluoride. Under these conditions, the potassium fluoride (KF) converts to potassium bifluoride (KHF2), which is the actual electrolyte. This potassium bifluoride aids electrolysis by greatly increasing the electrical conductivity of the solution. Fluorine gas forms at the anode, and hydrogen gas at the cathode.
HF + KF → KHF2
2 KHF2 → 2 KF + H2 + F2
A compound with molecular formula C₇H₁₆ shows optical isomerism , the compound will be
The unpaired electrons in Ni(CO)₄ are
Pyrolusite is a/an
Standard electrode potentials are Fe²⁺∕Fe (E° = -0.44) Fe³⁺∕Fe²⁺(E° = 0.77) Fe²⁺, Fe³⁺ and Fe blocks are kept together, then
Which one of the following indicates the value of the gas constant R ?
NaCl crystals consist of
Dalton's law of partial pressure is not applicable to
Aluminium becomes passive in
H₃PO₂ is the molecular formula of an acid of phosphorus. Its name and basicity respectively are
Which one of the following allotropic forms of carbon is isomorphous with crystalline silicon?
Which of the following is not correct?
There is S-S bond in
On boiling an aqueous solution of KCIO₃ with iodine the following product is obtained?
The indicator used in titrating oxalic acid with caustic soda solutions is
The pH of pure water at 25ºC is close to
Gypsum, CaSO₄.2H₂O on heating to about 120ºC, forms plaster of paris which has chemical composition represented by
Which of the following metal evolves hydrogen on reaction with cold dilute HNO₃?
β- particles are
Which buffer solution out of the following will have pH > 7?
The no. of isomers of saturated pentane are
Iodoethane reacts with sodium in ether to form
The half life of a radio active element is 30 min. One sixteenth of original quantity of element will be left after
Formic acid is obtained when
An organic compound 'X' on treatment with acidified K₂Cr₂O₇ gives a compound 'Y' which reacts with I₂ and sodium carbonate to form Triodomethane. The compound 'X' is
Which is not the resonance structure of aniline?
Ethylene reacts with 1% cold alkaline KMnO₄ to form
Among acetic acid,phenol and n-hexanol,which will react NaHCO3 to give sodium salt and carbondioxide ?
The co-ordination number of iron in [Fe(CN)₆]3⁻ is
Which of the following has the same oxidation state as that of Cr in K₂CrO₃
Bakelite is obtained from phenol by reacting with
Chlorine is in +1 oxidation state in
Anthracene is purified by
Phenol, p-Methylphenol, m-Nitrophenol and p-Nitrophenol follows order of increasing acidic strength
The ratio of cationic radius to anionic radius in an ionic crystal is greater than 0.732. Its co-ordination number is
The freezing point of a solution, prepared from 1.25 g of a non-electrolyte and 20 g of water is 271.9 K. If molar depression constant is 1.86 K mole⁻1, the molar mass of the solute will be
The weight of pure NaOH required to prepare 250 cm3 of 0.1 N solution is
Which out of the following is chiral in nature?
The adsorption of hydrogen by palladium is called
12 litre of hydrogen and 11.2 litre of chlorine are mixed and exploded. The composition in volume of the mixture will be
Stainless steel contains iron and carbon along with
The trace metal present in insulin is
Spindle fibres are formed of
Ringer solution possesses
Tracheae of Cockroach and Mammal are similar in having
The liquid portion of blood is referred to as _____.
Which of these can dissolve a blood clot?
Blood glucose levels are lowered by insulin because it stimulates
The centre of origin of rice plants is
Coriandrum sativum is the botanical name of
Which of the following is a function of insulin?
One of the following is grown as a mixed crop
A drug from root which causes mental disorder and reduces blood pressure is obtained from
The bacterial disease which is found in chickens, is
Coir of commerce comes from which part of coconut?
Trophic levels are linked with
Which of the following food chain may not be directly dependent upon solar energy?
Most of the food chains are composed of
Okazaki fragment are joined by enzyme
Which one of the following conditions though harmful in itself, is also a potential saviour from a mosquito borne infectious disease ?
Hypophysis is the alternate name of
Complete failure of the anterior lobe of pituitary causes
Vessels are found in
A plant of F₁-generation with genotype 'AABbCC' on selfing produces which of the following phenotypic ratio in F₂-generation?
Deficiency of vatimn A in the body results in insufficent rhodopsin in the rods which leads to
If two genes are present at the same locus and after interacting with each other produce different effects are called
Which of the following is not immunised by triple antigen?
Sequence of eye covering (outer to inner) is
Which of the following can be regarded as the best hormonal contraception method in breast feeding women?
Coelom is cavity between alimentary canal and body wall enclosed by
The lymphatic ducts will empty directly into the _____.
The thoracic duct empties directly into the _____ vein.
Cavity lodging lungs is
Veliger is the larval stage in:
Minerals absorbed by roots move to the leaf through
Best source of renewable energy is
Growing trees and shrubs in small pots is
Ribulose biphosphate carboxylase oxygenase is located inside
Classification of Takhtajan is included in
Who first of all indicated that water is electron donor in photosynthesis ?
Which one of the following substances plays an important role in biochemical defence of host plants?
Correct sequence of different stages of development is
Nitrogen fixation occurs in
Increase in the concentration of pollutants in higher trophic levels is called
Fluoride pollution mainly affects
Aneuploidy is commonly observed in different varieties of
Both corpus luteum and macula lutea is
The digested food in Leucosolenia is stored in
Maturation of stamens and pistils, at different times in the same flower, is called
*Energy required to form glucose from pyruvate is equivalent to
Middle layer of anther wall is secreted by secondary outer parietal tissue. This the characteristic of
Haemoglobin releases oxygen at the tissues if
Blood entering the systemic circulation carries high concentrations of
An underground specialised shoot with reduced disc like stem covered by fleshy leaves is
Flow of blood in dorsal blood vessel of Earthworm is
Anal cerci occur in
Which of the plant group has evolved most recently-
Blood entering the kidney is filtered by the