711. A wheat stone bridge is said to be balanced when____________________?
A. maximum current flows through the galvanometer branch
B. minimum current flows through the galvanometer branch
C. potential difference across galvanometer branch is maximum
D. potential difference across galvanometer branch is zero

712. A particle of mass m charge q and speed V enters a uniform magnetic radius r. The radius r of the circle is_________________?
A. independent mass m
B. directly proportional to m
C. directly proportional to q
D. directly proportional to B

713. If a current carrying solenoid is suspended freely it will__________________?
A. be rotating
B. come to rest in N-S direction
C. vibrating like galvanometer needle
D. comes to rest after rotation

714. A current carrying conductor is placed in a uniform magnetic field parallel to it. The magnetic force experienced by the conductor is _____________________?
A. F=1/B
B. F=1/Bsinθ
C. F/0
D. F=1/Bcosθ

715. When a particle of charge q and mass m enters into a uniform magnetic field B moving with a velocity v perpendicular to the direction for the field it describes a circular path of radius___________________?
A. R=qB/mV
B. R=mV/qB
C. R=qmV/B
D. R=qmB/V

716. A magnetic compass will be deflected if it is kept near a____________________?
A. charge in motion
B. charge at rest
C. both
D. none

717. If the plane of the rectangular coil is parallel to the magnetic field (i.e radial magnetic field) the torque on the coil is_____________________?
A. τ = NIAB cosφ
B. τ = NIAB sinφ
C. τ = NIAB tanφ
D. τ = NIAB

718. 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

719. The charged particle enters the uniform magnetic field in such a way that its initial velocity is not perpendicular to the field the orbit will be__________________?
A. a circle
B. a spiral
C. an ellipse
D. helix

720. 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