Science (English Medium) Class 12 - CBSE Question Bank Solutions for Physics

A magnetic dipole is under the influence of two magnetic fields The angle between the field directions is 60° and one of the fields has a magnitude of 1.2 × 10^–2 T. If the dipole comes to stable equilibrium at an angle of 15° with this field, what is the magnitude of other field?

A very small magnet is placed in the magnetic meridian with its south pole pointing north. The null point is obtained 20 cm away from the centre of the magnet. If the earth¢s magnetic field (horizontal component) at this point be 0.3 gauss, the magnetic moment of the magnet is ______.

A cell having an emf E and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by ______.

If n cells each of emf e and internal resistance r are connected in parallel, then the total emf and internal resistance will be ______.

The nature of parallel and anti-parallel currents are ______.

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 ______.

Which of the following is correct about magnetic monopole?

Which of the following graphs represents the correct variation of inductive reactance X_L with frequency u?

In a pure capacitive circuit if the frequency of ac source is doubled, then its capacitive reactance will be ______.

Which of the following graphs represents the correct variation of capacitive reactance X_c with frequency v u?

A straight line plot showing the terminal potential difference (V) of a cell as a function of current (I) drawn from it, is shown in the figure. The internal resistance of the cell would be then ______.

Three infinitely long parallel straight current-carrying wires A, B and C are kept at equal distance from each other as shown in the figure. The wire C experiences net force F. The net force on wire C, when the current in wire A is reversed will be ______.

Draw a ray diagram of compound microscope for the final image formed at least distance of distinct vision?

An angular magnification of 30X is desired using an objective of focal length 1.25 cm and an eye piece of focal length 5 cm. How will you set up the compound microscope for the final image formed at least distance of distinct vision?

Figure shows some equipotential lines distributed in space. A charged object is moved from point A to point B.

(i)	(ii)	(iii)

Two batteries of emf ε₁ and ε₂ (ε₂ > ε₁) and internal resistances r₁ and r₂ respectively are connected in parallel as shown in figure.

A cell of emf E and internal resistance r is connected across an external resistance R. Plot a graph showing the variation of P.D. across R, versus R.