A simple pendulum with charged bob is oscillating with time period T and lets θ be the angular displacement. If the uniform magnetic field switched ON in a direction perpendicular to the plane of oscillation then ___________.

(a)

time period will decrease but θ will remain constant

(b)

time period remain constant but θ will decrease

(c)

both T and θ will remain the same

(d)

both T and θ will decrease

Which of the following graphs shows the variation of magnetic induction B with distance 'r' from along wire carrying current?

(a)

(b)

(c)

(d)

Four wires each of length 2m are bent into four loops P, Q, R, and S, and then suspended into a uniform magnetic field as shown in the figure same current is passed in each loop. On which loop the couple will be the highest?

(a)

P

(b)

Q

(c)

R

(d)

S

Which one of the following represents current magnetic field lines?

(a)

(b)

(c)

(d)

The angle of dip at a place, when horizontal and vertical components of earth's field are equal is ______________.

(a)

45°

(b)

60°

(c)

30°

(d)

0°

The most suitable metal for permanent magnet is ______________.

(a)

copper

(b)

aluminium

(c)

steel

(d)

iron

When current is doubled deflection is also doubled in ______________.

(a)

moving coil galvanometer

(b)

tangent galvanometer

(c)

both of them

(d)

neither of two

An electron of mass 0.90 x 10^-30kg under the action of a magnetic field moves in a circle of 2cm radius at a speed of 3 x 10⁶ m/s if a proton of mass 1.8 x 10^-27 kg was to move in a circle of the same radius in the same magnetic field, then its speed will be _______________.

(a)

3.0 x 10⁶ m/s

(b)

1.5 x 10³ m/s

(c)

6.0 x 10⁴ m/s

(d)

cannot be estimated from the same data

A long straight conductor carrying a current lies along the axis of a ring. The conductor will exert a force on the ring if _______________.

(a)

carries a current

(b)

has uniformly distributed charge

(c)

has non-uniformly distributed

(d)

none of the above

A current carrying conductor is associated with  _______________.

(a)

electric field

(b)

magnetic field

(c)

electro magnetic

(d)

all these

The direction of the magnetic force on a positive charge moving in a magnetic field is given by ________________.

(a)

thumb rule

(b)

left hand rule

(c)

right hand rule

(d)

cork screw rule

If a current I is flowing in a straight wire parallel to the x-axis and magnetic field is in the y-axis then the wire experiences in _________________.

(a)

in Z-direction

(b)

in Y- direction

(c)

no force

(d)

in X- diection

Consider the motion of a charged particle in a uniform magnetic field directed into the paper. If velocity v of the particle is in the plane of the paper, the charged particle will describe a _____________.

(a)

straight line

(b)

circle

(c)

ellipse

(d)

hyperbola

Lorentz force generally refers to force experienced by a charge due to combined action of _________________.

(a)

magnetic fields

(b)

electric fields

(c)

electric, magnetic & gravitational fields

(d)

electric and magnetic fields

Cyclotron is used to _______________.

(a)

accelerate charged particles or ions to low voltages

(b)

decelerate charged particles or ions to high voltages

(c)

accelerate charged particles or ions to high energies

(d)

accelerate charged particles or ions to high voltages