Electric Charges and Fields — Physics STD 12 Science — Question

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

(a) In the plane of paper pointing towards right

(b) In the plane of paper pointing towards left

(c) Perpendicular to the plane of paper and down‑wards

(d) Perpendicular to the plane of paper and upwards

In Young's double slit experiment how many maximas can be obtained on a screen (including the central maximum) on both sides of the central fringe if λ = 2000 and d = 7000  

(a) 12

(b) 7

(c) 18

(d) 4

A transverse wave travels along the Z-axis. The particles of the medium must move:

1. Along the Z-axis
2. Along the X-axis
3. Along the Y-axis
4. In the X-Y plane.

Two electric bulbs rated  watt V volts and   watt V volts are connected in parallel and V volts are applied to it. The total power will be    

(a)  watt

(b)  watt

(c)

(d)

Which of the following option represents Amperemaxwell Law ?

If in a coil rate of change of area is 5 m²/milli second and current become 1 amp from 2 amp in 2  If magnitude of field is 1 tesla then self inductance of the coil is

(a) 2 H

(b) 5 H

(c) 20 H

(d) 10 H

The graph Shows the variation in magnetic flux ∅(t) with time through a coil. Which of the statements given below is not correct

(a) There is a change in the direction as well as magnitude of the induced emf between B and D

(b) The magnitude of the induced emf is maximum between B and C

(c)There is a change in the direction as well as magnitude of induced emf between A and C

(d) The induced emf is zero at B

An oxide coated filament is useful in vacuum tubes because essentially

(a) It has high melting point

(b) It can withstand high temperatures

(c) It has good machanical strength

(d) It can emit electrons at relatively lower temperatures

A small coil of N turns has area A and a current I flows through it. The magnetic dipole moment of this coil will be

(a) NI/A

(b)

(c)

(d) NIA

In a transistor configuration b-parameter is

(a)

(b)

(c)

(d)