Moving Charges and Magnetism — Physics STD 12 Science — Question

The intensity of electric field at a point between the plates of a charged capacitor(a) Is directly proportional to the distance between the plates(b) Is inversely proportional to the distance between the plates(c) Is inversely proportional to the square of the distance between the plates(d) Does not depend upon the distance between the plates

Which of the following is used to investigate the structure of solids?

If the current is doubled, the deflection is also doubled in(a) A tangent galvanometer(b) A moving coil galvanometer(c) Both (a) and (b)(d) None of these

The wave theory in its original form was first postulated by:

A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm  are kept along the same axis with the distance d between them. If a parallel beam of light falling on  A leaves B as a parallel beam, then distance d in cm will be(a) 25(b) 15(c) 30       (d) 50

The alloys constantan and manganin are used to make standard resistance due to they have(a) Low resistivity(b) High resistivity(c) Low temperature coefficient of resistance(d) Both (b) and (c)

When the current flowing in a circular coil is doubled and the number of turns of the coil in it is halved, the magnetic field at its centre will become (a) Four times(b) Same(c) Half(d) Double

X-ray will travel minimum distance in(a) Air(b) Iron(c) Wood(d) Water