Two thick wires and two thin wires, all of the same materials and same length form a square in the three different ways P, Q and R as shown in fig with current connection shown, the magnetic field at the centre of the square is zero in cases
|
(a) In P only |
(b) In P and Q only |
(c) In Q and R only |
(d) P and R only |
(d) P and R only
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Switch S of the circuit shown in figure. is closed at t = 0. If e denotes the induced
emf in L and i, the current flowing through the circuit at time t, which of the following graphs is correct
|
(a)
|
(b)
|
(c)
|
(d)
|
The de-Broglie wavelength of a particle moving with a velocity 2.25 × 108 m/s is equal to the wavelength of photon. The ratio of kinetic energy of the particle to the energy of the photon is (velocity of light is 3 × 108 m/s)
|
(a) 1/8 |
(b) 3/8 |
(c) 5/8 |
(d) 7/8 |
The wing span of an aeroplane is 20 metre. It is flying in a field, where the vertical component of magnetic field of earth is 5 × 10–5 tesla, with velocity 360 km/h. The potential difference produced between the blades will be
|
(a) 0.10 V |
(b) 0.15 V |
(c) 0.20 V |
(d) 0.30 V |
When a plane mirror is placed horizontally on a level ground at a distance of 60 m from the foot of a tower, the top of the tower and its image in the mirror subtend an angle of 90° at the eye. The height of the tower will be
| (a) 30 m | (b) 60 m | (c) 90 m | (d) 120 m |
