The magnetic field in a coil of 100 turns and 40 square cm area is increased from 1 Tesla to 6 Tesla in 2 second. The magnetic field is perpendicular to the coil. The e.m.f. generated in it is 

(1) 10⁴ V

(2) 1.2 V

(3) 1.0 V

(4) 10^–2 V

A metallic ring connected to a rod oscillates freely like a pendulum. If now a magnetic field is applied in the horizontal direction so that the pendulum now swings through the field, the pendulum will:

An aluminium ring \(B\) faces an electromagnet \(A\). If the current \(I\) through \(A\) can be altered, then:

A coil having n turns and resistance R Ω is connected with a galvanometer of resistance 4R Ω. This combination is moved in time t seconds from a magnetic field W₁ $weber/m^2$ to W₂ $weber/m^2$. If area of each turn is 1 m² , the induced current in the circuit is-

(1) $-\frac{W_2-W_1}{5Rnt}$

(2) $-\frac{n(W_2-W_1)}{5Rt}$

(3) $-\frac{(W_2-W_1)}{Rnt}$

(4) $-\frac{n(W_2-W_1)}{Rt}$

A rectangular coil ABCD is rotated anticlockwise with a uniform angular velocity about the axis shown in the diagram below. The axis of rotation of the coil as well as the magnetic field B are horizontal. The induced e.m.f. in the coil would be maximum when 

(1) The plane of the coil is horizontal

(2) The plane of the coil makes an angle of 45° with the magnetic field

(3) The plane of the coil is at right angles to the magnetic field

(4) The plane of the coil makes an angle of 30° with the magnetic field

Two rails of a railway track insulated from each other and the ground are connected to a milli voltmeter. What is the reading of voltmeter, when a train travels with a speed of 180 km/hr along the track. Given that the vertical component of earth's magnetic field is 0.2 × 10^–4 weber/m² and the rails are separated by 1 metre 

(1) 10^–2 volt

(2) 10^–4 volt

(3) 10^–3 volt

(4) 1 volt

A conducting square loop of side L and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides. A magnetic induction B constant in time and space, pointing perpendicular and into the plane of the loop exists everywhere. The current induced in the loop is

(1) $\frac{Blv}{R}$ clockwise

(2) $\frac{Blv}{R}$ anticlockwise

(3) $\frac{2Blv}{R}$ anticlockwise

(4) Zero

A conducting wire is moving towards the right in a magnetic field B. The direction of the induced current in the wire is shown in the figure. The direction of the magnetic field will be:

One conducting U tube can slide inside another as shown in figure, maintaining electrical contacts between the tubes. The magnetic field B is perpendicular to the plane of the figure. If each tube moves towards the other at a constant speed v then the emf induced in the circuit in terms of B, l and v where l is the width of each tube, will be 

(1) Zero

(2) 2 Blv

(3) Blv

(4) – Blv

The magnitude of the earth’s magnetic field at a place is B₀ and the angle of dip is δ. A horizontal conductor of length l lying along the magnetic north-south moves eastwards with a velocity v. The emf induced across the conductor is:
1. Zero
2. B₀lv sinδ
3. B₀lv
4. B₀lv cosδ