List of practice Questions

The thickness of a uniform rectangular metal plate is 5 mm and the area of each surface is 3750 cm\(^2\). In steady state, the temperature difference between the two surfaces of the plate is 14°C. If the heat flowing through the plate in one second from one surface to the other surface is 42 J, then the thermal conductivity of the metal is:
The ratio of the specific heat capacities of a gas is 1.5. When the gas undergoes an adiabatic process, its volume is doubled and pressure becomes \( P_1 \). When the gas undergoes isothermal process, its volume is doubled and pressure becomes \( P_2 \). If \( P_1 = P_2 \), the ratio of the initial pressures of the gas when it undergoes adiabatic and isothermal processes is:
If \( E_c \) and \( E_v \) represent the energy of the conduction band and valence band, \( E_D \) represent the donor energy level, and the band gap in a n-type semiconductor, then the true relation among them is:
Out of the following pair of elements, identify isotones:
Plutonium nucleus undergoes fission with:
If the frequency of the incident light on a metal surface is increased by 10%, then the kinetic energy of the emitted photoelectrons is increased from 0.5 eV to 0.7 eV. Then the work function of the metal is:
The de Broglie wavelength associated with the electrons accelerated by a potential of 81 V is lying in the region of electromagnetic waves:
In an Young double slit experiment without varying the distance of the screen and the slit separation, if the wavelength of monochromatic source is changed one by one in the ratio 2:3:4, then the corresponding fringe widths measured will be in the ratio:
If the power of a lens is -2.0 D, then the type and focal length \( f \) of the lens are:
If a ray of light passes through a medium, its frequency and wavelength are \( 4 \times 10^{14} \) Hz and 450 nm respectively. Then the refractive index of the medium is:
The electromagnetic waves used in LASIK and cell phones are respectively:
The ratio between the magnetic dipole moment of a revolving electron in a circular orbit to its angular momentum is (where \( e \) is the charge and \( m \) is the mass of the electron):
In an LCR resonance circuit at resonance frequency \( \omega_0 \), the quality factor \( Q \) is:
The mutual inductance between a pair of coils A and B placed close to each other depends upon:
Two straight long parallel wires carrying equal amounts of current in opposite directions placed 5 cm apart repel each other by a force \( F \). If the current in one of the wires is doubled and reversed, then the force between them is:
A proton with kinetic energy of 2 MeV is describing a circular path of radius \( R \) in a uniform magnetic field. The kinetic energy of the deuteron to describe the same circular path in the same field is:
If a charged particle enters a uniform magnetic field \( B \), with a velocity \( v \) such that \( v \) has a component along \( B \), then the charged particle describes:
The work done by a source in taking unit charge from lower to higher potential energy is called the source's:
The electric field intensity due to an ideal dipole at a distance \( r \) from its center on the axial point is directly proportional to:
The equipotential surface is:
A man fires bullets at two hillocks, one shorter and the other taller. The taller one is behind the smaller one. If the first echo is heard after 6 s and the second echo after 12 s, then the distance between the hillocks is (velocity of sound in air = 330 m/s):
The ratio of the respective rms velocities of the gas molecules of an ideal gas at 327°C and at 627°C is:
In a Carnot engine, the temperature of the sink is 350 K. If the efficiency of the engine is 50%, the temperature of the source should be:
If an ideal gas, in an insulated vessel, is allowed to expand into another similar evacuated vessel through a valve then:
Two gases under the same thermal conditions have the same number of molecules per unit volume. If the respective molecular diameters of the gases are in the ratio 1 : 3, then their respective mean free paths are in the ratio: