What will be the phase difference between virtual voltage and virtual current, when the current in the circuit is wattless
Isotopes are atoms having
The resonant frequency of a circuit is f. If the capacitance is made 4 times the initial value, then the resonant frequency will becomes
f = 2π/√LC
∴ f' = 2π/√4LC = 1/2 x 2π/√LC = f/2
A body is moving in a circular path with a constant speed. It has
In an inelastic collision between two bodies, the physical quantity that is conserved
The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be
Since the volume will remain the same
And the wire is in the form of a cylinder
πr12l1 = πr22l2
so there fore
r12l1 = r22l2
so on l1 is the initial length, which is streched n times to the final length
l1 = l,,,,, l2 = nl
on substituing the values
R2 = n2R
Here in this question the value of n will be 2 as the length is increased by on substituing the value
R2 = 4R
Which is a 300% increase
The ratio of the lengths of two wires A and B of same material is 1:2 and the ratio of their diameter is 2:1. They are stretched by the same force, then the ratio of increase in length will be
Photons of energy 6eV are incident on a metal surface whose work function is 4eV. The minimum kinetic energy of the emitted photoelectrons will be
Minimum kinetic energy is always zero.
Consider the following statement for a bridge type rectifier
1. Centre tap is not required for the secondary of the transformer.
2. The output will be half wave rectification if one of the diodes of the bridge circuit gets open circuited.
3. The bridge requires four diodes
4. If one of the diodes gets short circuited, the transformer will be short circuited.
Which of the above statements are correct?
On the horizontal surface of a truck (μ=0.6), a block of mass 1 kg is placed.If the truck is accelerating at the rate of 5 m/sec2 then frictional force on the block will be
Two electric charge 12 μ C and − 6 μ C are places 20 cm apart in air. There will be a point P at which electric potential is zero on the line joining these two charges and outside, excluding the region between them. The distance of P from − 6 μ C charge is
The maximum wavelength of radiation emitted at 2000 K is 4 μm. What will be the maximum wavelength of radiation emitted at 2400 K?
The mass of the moon is about 1.2% of the mass of the earth. Compared to the gravitational force the earth exerts on the moon, the gravitational force the moon exerts on earth
If pressure of a gas contained in a closed vessel is increased by 0.4% when heated by 1oC, the initial temperture must be
A lift is moving down with an acceleration a. A man in the drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift, and a man standing stationary on the ground are respectively
The domain formation is a necessary feature of
The coil of a moving coil galvanometer is wound over a metal frame in order to
A car accelerated from initial position and then returned at initial point, then
The change in surface energy, when a drop of surface tension T and radius of R splits into 1000 droplets of radius r, is
The general motion in three dimensions may be
A person of 70kg mass is lifted by a helicopter with the help of rope hanging from it. If the helicopter is rising with an acceleration of 4 ms-2, the tension in the rope is (g=10 ms-2)
The force constant of two springs are k1 and k2 respectively. Both are stretched till their potential energies are equal. The forces f1 and f2 applied on them are in the ratio
Potential energy of spring u = 1/2 = kx2
k = force constant, x = increase in length
u1 = 1/2 k1x12
u2 = 1/2 k2x22
According to question
u1 = u2
1/2 k1x12 = 1/2 k2x22
A ball is projected upwards from the top of tower with a velocity 50 ms-1 making an angle 30owith the horizontal. The height of the tower is 70 m. After how many seconds from the instant of throwing will the ball reach the ground?
In a streamline flows if the gravitational head is h. The kinetic and pressure heads are
While viewing a distant object with a telescope, suddenly a housefly sits on objective lens. The correct statement is that
The moment of Inertia of a solid cylinder of mass M and radius R about a line parallel to the axis of the cylinder but lying on the surface of the cylinder is
The density of a cube is measured by measuring its mass and length of its sides. If the maximum error in the measurement of mass and length are 4% and 3% respectively, then the maximum error in the measurement of density would be
Small droplets of a liquid are usually more spherical in shape than larger drops of the same liquid because
If the cold junction of thermocouple is lowered, then the neutral temperature
A vessel is filled with an ideal gas at a pressure of 20 atm and is at a temperature of 27 oC . One half of the mass is removed from the vessel and the temperature of the remaining gas is increased to 87 oC . At this temperature the pressure of the gas will be ...
A gas for which γ = 1.5 is suddenly compressed to 1/4 th of the initial volume. Then the ratio of the final to initial pressure is
The dimensional formula for the modulus of rigidity is
For which property are electrons used in an electron microscope?
16 tunning forks are arranged in the order of increasing frequencies. Any two successive forks give 8 beats per sec when sounded together. If the frequency of the last fork is twice the first, then the frequency of the first fork is
The K.E. acquired by a mass m in travelling a certain distance d. starting from rest, under the action of a constant force is directly proportional to
The compound which can form intramolecular hydrogen bond is
In which of the following reactions, both oxidised and reduced forms of the same compound are obtained?
The number of π -bonds in the product formed by passing acetylene through dil-H2SO4 containing mercuric sulphate is
Which metal salt gives a violet coloured bead in the borax bead test?
Benzene is a monocyclic compound. It is armoatic because it contains
The energy of hydrogen atom in its ground state is -13.6 eV. The energy of the level corresponding to the quantum number n=5 is
1 mol of CH₄ contains
Which of the following food stuffs contains nitrogen?
Pi-bonds do not alter the shape, but merely shorten the
A carbon-carbon double bond consists of one sigma bond and one pi bond. This double bond is stronger than a single covalent bond (599 kJ/mol for C=C vs. 348 kJ/mol for C—C) and also shorter with an average bond length of 1.33 Angstroms (133 pm).
The acid showing salt like character in aqueous solutions is
Which of the following is paramagnetic species?
The enthalpy of hydrogenation of cyclohexene is -119.5 KJ mol-1 if resonance energy of benzene is -150.4 KJ mol-1,its enthalpy of hydrogenation would be
The state of equilibrium refers to
The rate of a first order reaction is 1.5 X 10-2 mol-L-1-min-1 at 0.5M concentration of the reactant. The half -life of the reaction is
Identify the correct statement regarding entropy
The IUPAC name of acraldehyde is
The I.P. of an element on going from left to right in a period
As we move from left to right in a period, the ionisation potential increases with increasing atomic numbers. This is because across a period the nuclear charge increases though the principal quamtum number of the valence shell remains the same. As a result, the valence electrons are more and more tightly held by the nucleus. Consequently, more energy is needed to remove the electrons and hence ionisation potential keeps on increasing.
The electroplating with chromium is undertaken because
The gas molecules have rms velocity of its molecules as 100 m/s. What is its average velocity ?
Crude naphtha is a mixture of
Which is the strongest Lewis base ?
Only two isomeric monochloro derivatives are possible for:
1 g of radioactive element reduces to 125 mg after 24 hours. Half life of isotope is
Iodoform is formed on warming l₂ and NaOH with
Polymerisation in which two or more chemically different monomers take part is called
Which group decreases acidic nature of phenol?
The best method for the separation of napthalene and benzoic acid from their mixture is :
Semiconductors are derived from compounds of
10 ml. of N-HCl, 20 ml of N/2 H₂SO₄ and 30 ml of N/3 HNO₃ are mixed together and volume made to one litre. The normality of the resulting solution is
IdentifyX in the sequence given below :
In acidic medium, one mole of MnO₄- accepts how many moles of electrons in a redox process ?
In an antifluorite structure, cations occupy
If 75.5g of a metallic chloride contains 35.5g of chlorine, then the equivalent weight of the metal is
In Faraday-Tyndall effect the colloidally suspended particles
Tyloses are thickenings seen in
A bladder like structure are formed during the secondary growth and blocks the continuity of the secondary growth and blocks the continuity of the conducting system. It is known as tyloses which found in xylem cells and ray parenchyma.
Breeding place of Flaming (Hansawar) in India is
Number of linkage groups in Pisum Sativum is
Which of these can dissolve a blood clot?
Causative agent of syphilis is :
The alimentary tube is around _____ meters long.
The Indian soils are generally poor in
Which of the following animal is the most economical 'Meat making machine'?
Neanderthal man lived in
As a result of oblique cleavage the symmetry produced is known as :
During ovulation, a(n) _____________ is released from the ovary.
Which of the following lies between replication and translocation ?
DNA replication is
A cross involving F1 hybrid and a double recessive parent is called :
Percentage of heterozygous individuals obtained from selfing Rr individuals is :
Receptors of pressure present in deep layers of skin are
Chemical knives/molecular scissors of DNA are
According to the sliding filament theory of muscle contraction
Involuntary muscular contraction is called
The distribution of sodium and potassium ions during resting potential is maintained by
The correct sequence for the transmission of a nerve impulse along a neuron is
1. Potassium gates open.
2. Sodium ions diffuse into neuron.
3. Resting potential.
The primitive atmosphere of earth contained water vapours, hydrogen, ammonia and
The process of photosynthesis is
The plants respond to photoperiods due to the presence of
Hydrophytes are able to float due to presence of
Which of the following is the most dangerous metal pollutant of automobile exhaust?
Which of the following store sperm cells and eliminate those that have major genetic defects?
Occasionally, three polar bodies are found clinging to the mature ovum. One came from the unequal division of the ovum; but what about the other two?
Which one requires oxygen
Use the following information to answer the question :
What is the order in which air passes through these structures during inhalation?
The number of bones in appendicular skeleton are
Cucurbitaceae has plant yielding a vegetable fruits what is the position of this family in Bentham and Hooker classification-
The antibiotic used in Lederberg's replica plating experiment was
Inter-articulated disc is found in
The tonicity of the tissue surrounding the loop of Henle is vital to the maintenance of blood volume because it