Q. A current-carrying conductor would move when placed in a magnetic field was discovered by?
Answer: Andre Ampere
Q. The most commonly used material in semiconductor devices is?
Answer: Silicon
Q. When a forward bias is applied to a p-n junction, the concentration of electrons on the p-side?
Answer: Increases dramatically
Q. If an electron has zero orbital angular momentum, the magnitude of its magnetic dipole moment equals:
Answer: 0
Q. The Fermi level in an intrinsic semiconductor lies?
Answer: In the middle of the valence & conduction bands
Q. In a photoelectric effect experiment at a frequency above cut off, the stopping potential is proportional to?
Answer: The energy of the most energetic electron after it is ejected
Q. If the material has resistivity (Ω-cm) in the range of 10⁵ to 10⁹, then the material is termed as an?
Answer: Insulator
Q. Which of the following bodies has the largest kinetic energy?
Answer: Mass 2M and speed 3V
Q. For a pure semiconductor, the Fermi level is?
Answer: At the center of the gap between the valence and conduction bands
Q. The energy gap (in eV) between the valence and conduction bands of an insulator is of the order of?
Answer: 5
Q. Photons in a laser beam have the same energy, wavelength, polarization direction, and phase because?
Answer: Each is produced in an emission that is stimulated by another
Q. The Pauli’s exclusion principle is obeyed by?
Answer: All particles with spin quantum numbers of 1/2
Q. The ground state energy of an electron in a one-dimensional trap with zero potential energy in the interior and infinite potential energy at the walls?
Answer: Is independent of temperature
Q. The probability that a particle is in a given small region of space is proportional to?
Answer: The square of the magnitude of its wave function
Q. Maxwell’s equations predict that the speed of light in free space is?
Answer: Independent of frequency
Q. Consider: radio waves (r), visible light (v), infrared light (i), x-rays (x), and ultraviolet light (u). In order of increasing frequency, they are?
Answer: r, i, v, u, x
Q. A Bloch wave represents the motion of an electron in?
Answer: Periodic potential
Q. Which of the following pieces of experimental evidence contributed to the development of quantum mechanics?
Answer: Photoelectric effect
Q. A three-dimensional array of points, each of which has identical surroundings is called?
Answer: Space lattice
Q. Hall’s effect is used to measure the?
Answer: Carrier concentration
Q. Which of the following unit cells has the highest symmetry?
Answer: Cubic
Q. Lenz’s law is the consequence of the law of conservation of?
Answer: Law of conservation of energy
Q. The temperature coefficient of resistance for a semiconductor is?
Answer: Negative
Q. The electrical conductivity of a semiconductor?
Answer: Increases with increase in temperature
Q. Of the three chief kinds of magnetic materials (diamagnetic, paramagnetic, and ferromagnetic), which are used to make permanent magnets?
Answer: Only ferromagnetic
Q. In Bragg’s equation (2dsinθ = nλ), ‘n’ represents:
Answer: The order of reflection
Q. In an oscillating LC circuit, the total stored energy is U. The maximum energy stored in the capacitor during one cycle is?
Answer: U
Q. Each plate of a capacitor stores a charge of magnitude 1 mC when a 100 V potential difference is applied. The capacitance is:
Answer: 10 μF
Q. The units of magnetic dipole moment are:
Answer: Ampere meter²
Q. The torque exerted by an electric field on a dipole is?
Answer: Perpendicular to both the field and the dipole moment
Q. Heat has the same units as?
Answer: Work
Q. 10C of charges are placed on a spherical conducting shell. A particle with a charge of –3C is placed at the center of the cavity. The net charge on the inner surface of the shell is:
Answer: +3C
Q. When the temperature of a copper penny is increased by 100 °C, its diameter increases by 0.17%. The area of one of its faces increases by:
Answer: 0.34%
Q. Why do raindrops fall with constant speed during the later stages of their descent?
Answer: Air resistance just balances the force of gravity
Q. Suppose A = BC, where A has the dimension L/M and C has the dimension L/T. Then B has the dimension:
Answer: T/M
Q. The unit of magnetic flux density is ______?
Answer: Wb m⁻²
Q. The force exerted by a uniform electric field on a dipole is:
Answer: None of these (Net force is zero in a uniform field)
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