An electron is moving with velocity m/s in an electric field of intensity volt/m and a magnetic field of tesla. Find the magnitude of force on the electron.
The ratio of magnetic field and magnetic moment at the centre of a current carrying circular loop is x. When both the current and radius is doubled the ratio will be
x/8
x/4
x/2
2x
Current through ABC and A' B'C' is I. What is the magnetic field at P ? BP = PB' = r (Here C' B' PBC are collinear)
Zero
The magnetic field at the point of intersection of diagonals of a square wire loop of side L carrying a current I is
A straight wire of length 2 m carries a current of 10 A. If this wire is placed in a uniform magnetic field of 0.15 T making an angle of 45° with the magnetic field, the applied force on the wire will be
1.5 N
3 N
A magnetic needle is placed in a uniform magnetic field and is aligned with the field. The needle is now rotated by an angle of 60° and the work done is W. The torque on the magnetic needle at this position is
When a proton is released from rest in a room, it starts with an initial acceleration a0 towards west. When it is projected towards north with a speed v0 it moves with an initial acceleration 3a0 towards west. The electric and magnetic fields in the room are
A current loop in a magnetic field
experiences a torque whether the field is uniform or non- uniform in all orientations
can be in equilibrium in one orientations
can be equilibrium in two orientations, both the equilibrium states are unstable
can be in equilibrium in two orientations, one stable while the other is unstable
A bar magnet of length l and magnetic dipole moment M is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be
M
A galvanometer having internal resistance 10 Ω requires 0.01 A for a full scale deflection. To convert this galvanometer to a voltmeter of full-scale deflection at 120 V, we need to connect a resistance of
11990 Ω in series
11990 Ω in parallel
12010 Ω in series
12010 Ω in parallel