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

A parallel beam of light of wavelength 560 nm falls on a thin film of oil (refractive index = 1.4). What should be the minimum thickness of the film so that it strongly reflects the light?

A parallel beam of white light is incident normally on a water film 1.0 × 10⁻⁴ cm thick. Find the wavelengths in the visible range (400 nm − 700 nm) which are strongly transmitted by the film. Refractive index of water = 1.33.

A glass surface is coated by an oil film of uniform thickness 1.00 × 10⁻⁴ cm. The index of refraction of the oil is 1.25 and that of the glass is 1.50. Find the wavelengths of light in the visible region (400 nm − 750 nm) which are completely transmitted by the oil film under normal incidence.

Plane microwaves are incident on a long slit of width 5.0 cm. Calculate the wavelength of the microwaves if the first diffraction minimum is formed at θ = 30°.

Why does a compass needle get deflected when brought near a bar magnet?

A double convex lens is made of a glass of refractive index 1.55, with both faces of the same radius of curvature. Find the radius of curvature required, if the focal length is 20 cm.

How does Ampere-Maxwell law explain the flow of current through a capacitor when it is being charged by a battery? 

Write the expression for the displacement current in terms of the rate of change of electric flux. 

A circular coil of cross-sectional area 200 cm² and 20 turns is rotated about the vertical diameter with angular speed of 50 rad s⁻¹ in a uniform magnetic field of magnitude 3.0 × 10⁻²T. Calculate the maximum value of the current in the coil.

Show diagrammatically how an alternating emf is generated by a loop of wire rotating in a magnetic field. Write the expression for the instantaneous value of the emf induced in the rotating loop.

Two nuclei have mass numbers in the ratio 1: 2. What is the ratio of their nuclear densities?

Can two equi-potential surfaces intersect each other? Give reasons.

Two charges −q and +q are located at points A (0, 0, −a) and B (0, 0, +a) respectively. How much work is done in moving a test charge from point P (7, 0, 0) to Q (−3, 0, 0)?

A charge ‘q’ moving along the X- axis with a velocity  `vecv` is subjected to a uniform magnetic field B along the Z-axis as it crosses the origin O.

(i) Trace its trajectory.

(ii) Does the charge gain kinetic energy as it enters the magnetic field? Justify your answer.

In motor vehicles, a convex mirror is attached near the driver's seat to give him the view of the traffic behind. What is the special function of this convex mirror which a plane mirror can not do?

If an object far away from a convex mirror moves towards the mirror, the image also moves. Does it move faster, slower or at the same speed as compared to the object?

Can mirrors give rise to chromatic aberration?

In image formation from spherical mirrors, only paraxial rays are considered because they

Following figure  shows three transparent media of refractive indices \[\mu_1 ,    \mu_2   \text{ and }  \mu_3\].  A point object O is placed in the medium \[\mu_2\].  If the entire medium on the right of the spherical surface has refractive index  \[\mu_3\], the image forms at O". In the situation shown,

A U-shaped wire is placed before a concave mirror having radius of curvature 20 cm as shown in figure. Find the total length of the image.