PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions

Which of the following are electromagnetic waves?

Suppose Swarglok (heaven) is in constant motion at a speed of 0.9999c with respect to the earth. According to the earth's frame, how much time passes on the earth before one day passes on Swarglok?

If a person lives on the average 100 years in his rest frame, how long does he live in the earth frame if he spends all his life on a spaceship going at 60% of the speed of light.

When the diode shows saturated current, dynamic place resistance is _____________ .

Electric charges are distributed in a small volume. The flux of the electric field through a spherical surface of radius 10 cm surrounding the total charge is 25 V m. The flux over a concentric sphere of radius 20 cm will be _____________ .

Define self-inductance of a coil.

Drive the expression for electric field at a point on the equatorial line of an electric dipole.

Depict the orientation of the dipole in (i) stable, (ii) unstable equilibrium in a uniform electric field.

A power transmission line feeds input power at 2200 V to a step-down transformer with its primary windings having 300 turns. Find the number of turns in the secondary to get the power output at 220 V.

Derive the expression for the electric potential due to an electric dipole at a point on its axial line.

Depict the equipotential surfaces due to an electric dipole. 

Radiation of frequency 10¹⁵ Hz is incident on two photosensitive surface P and Q. There is no photoemission from surface P. Photoemission occurs from surface Q but photoelectrons have zero kinetic energy. Explain these observations and find the value of work function for surface Q.

(i)Obtain the expression for the torque `vecτ` experienced by an electric dipole of dipole moment `vecP` in a uniform electric field, `vecE` .

(ii) What will happen if the field were not uniform?

In the figure given below the input waveform is converted into the output waveform by a device ‘X’. Name the device and draw its circuit diagram.

In a single slit diffraction experiment, when tiny circular obstacle is placed in path of light from a distance source, a bright spot is seen at the centre of the shadow of the obstacle. Explain why?

State two points of difference between the interference patterns obtained in Young’s double slit experiment and the diffraction pattern due to a single slit.

Describe briefly, with the help of labelled diagram, working of a step-up transformer.

A step-up transformer converts a low voltage into high voltage. Does it not violate the principle of conservation of energy? Explain.

Will the diffraction effects from a slit be more or less clearly visible if the slit-width is increased?

An electric dipole is placed in an electric field generated by a point charge.