The net electric field is zero:
A) Inside any conductor
B) Inside any conductor with a static charge
C) Inside any material, conductor or insulator, with a static charge
D) The electric field cannot be zero
An electric field exerts a torque on a dipole only if:
A) The field is parallel to the dipole moment
B) The field is negative
C) The field is perpendicular to the dipole moment
D) The field is positive
When N-type semiconductor is heated?
A) Number of electrons increases while that of holes decreases
B) Number of holes increases while that of electrons decreases
C) Number of electrons and holes remain same
D) Number of electron and holes increases equally
Which of these is the best description of a Zener diode
A) It operates in reverse region
B) It is a constant voltage device
C) It is a constant current device
D) All of these
Two charges are placed a certain distance apart in air. When a dielectric sheet is placed between them, the electrostatic force between them will
A) Decrease
B) Increase
C) Remain unchanged
D) Become zero
What is required in a fusion reactor, in order to over come the electrostatic repulsive force between nuclides?
A) Very high pressure
B) Very high temperature
C) Very small volume
D) All of these
The period of the Physical Pendulum is
A) T=2π√I/mgd
B) T=2π√1/d
C) T=2π√Lg
D) All of these
Over-damping results in
A) Slower return to equilibrium
B) Faster turn to equilibrium
C) Equilibrium ever achieved
D) Unrhythmic return to equilibrium
Two spheres of same material have radii R1 and R2 They are heated to same temperature and kept in same enclosure at low temperature. Their rates of loss of heat are in the ratio:
A) R21/R22
B) R1/R2
C) R22/R21
D) R2/R1
Which of the following statement is wrong?
A) Rough surfaces are better radiators than smooth surfaces
B) Highly polished mirror surfaces are very good radiators
C) Black surfaces are better absorbers than white one
D) Black surfaces are better radiators then white ones
