Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Physics

Assertion: The poles of magnet can not be separated by breaking into two pieces.

Reason: The magnetic moment will be reduced to half when a magnet is broken into two equal pieces.

Which of the following statement is true?

Which of the following statements is false for a perfect conductor?

Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator is ______.

Three Charges 2q, -q and -q lie at vertices of a triangle. The value of E and V at centroid of triangle will be ______.

A solid spherical conductor has charge +Q and radius R. It is surrounded by a solid spherical shell with charge -Q, inner radius 2R, and outer radius 3R. Which of the following statements is true?

A test charge q is made to move in the electric field of a point charge Q along two different closed paths (Figure). First path has sections along and perpendicular to lines of electric field. Second path is a rectangular loop of the same area as the first loop. How does the work done compare in the two cases?

Kirchhoff’s junction rule is a reflection of ______.

1. conservation of current density vector.
2. conservation of charge.
3. the fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction.
4. the fact that there is no accumulation of charges at a junction.

Kirchhoff’s junction rule is a reflection of ______.

1. conservation of current density vector.
2. conservation of charge.
3. the fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction.
4. the fact that there is no accumulation of charges at a junction.

In a meter bridge the point D is a neutral point (Figure).

1. The meter bridge can have no other neutral point for this set of resistances.
2. When the jockey contacts a point on meter wire left of D, current flows to B from the wire.
3. When the jockey contacts a point on the meter wire to the right of D, current flows from B to the wire through galvanometer.
4. When R is increased, the neutral point shifts to left.

In a meter bridge the point D is a neutral point (Figure).

1. The meter bridge can have no other neutral point for this set of resistances.
2. When the jockey contacts a point on meter wire left of D, current flows to B from the wire.
3. When the jockey contacts a point on the meter wire to the right of D, current flows from B to the wire through galvanometer.
4. When R is increased, the neutral point shifts to left.

What are the advantages of the null-point method in a Wheatstone bridge? What additional measurements would be required to calculate `R_(unknown)` by any other method?

What are the advantages of the null-point method in a Wheatstone bridge? What additional measurements would be required to calculate `R_(unknown)` by any other method?

What is the advantage of using thick metallic strips to join wires in a potentiometer?

What is the advantage of using thick metallic strips to join wires in a potentiometer?

Why are alloys used for making standard resistance coils?

Why are alloys used for making standard resistance coils?

Power P is to be delivered to a device via transmission cables having resistance RC. If V is the voltage across R and I the current through it, find the power wasted and how can it be reduced.

Power P is to be delivered to a device via transmission cables having resistance RC. If V is the voltage across R and I the current through it, find the power wasted and how can it be reduced.