A. zero
B. equal to the restoring couple
C. greater than the restoring couple
D. smaller than the restoring couple
Electromagnetism
Which one of the following material is most suitable for making core of an electromagnet ?
A. air
B. steel
C. Cu-Ni alloy
D. soft iron
A magnetic field___________________?
A. always exerts a force on a charged particle
B. never exerts a force on a charged particles
C. exerts a force if the charged particle is moving in the direction of the magnetic field lines
D. exerts a force if the charged particle is moving perpendicular to the magnetic field lines
Value of permeability of free space in SI units is___________________?
A. 4πx10-9 WbA-1m-1
B. 4πx10-7 WbA-1m-1
C. 4πx10-10 WbA-1m-1
D. 4πx10-8 WbA-1m-1
A galvanometer basically is an instrument used to ____________________?
A. detect current in a circuit
B. measure current flowing through a circuit
C. measure voltage across a circuit
D. measure potential difference between two points in a circuit
What is the value of the current in a wire of 10cm long at the right angle to a uniform magnetic field of 0.5 Weber/m2 when the force acting on the wire is 5N ?
A. 1A
B. 10A
C. 100A
D. 1000A
Two parallel wires carrying currents in the opposite directions____________________?
A. repel each other
B. attract each other
C. have no effect upon each other
D. they cancel out their individual magnetic fields
Minimum current required to produce a deflection of 1 mm on a scale at a distance of 1 meter is__________________?
A. 0.1 A
B. 1:00 AM
C. current sensitivity
D. 1 m A
The deflection for 50 division of galvanometer is decreased to 25 divisions by shunt resistance of 12Ω. Galvanometer resistance is_____________?
A. 18Ω
B. 30Ω
C. 24Ω
D. 12Ω
Magnetic flux and flux density are related by___________________?
A. magnetic flux = flux density / area
B. magnetic flux = flux density x area
C. flux density = magnetic flux area
D. flux density = magnetic flux x area
