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

Show using a proper diagram how unpolarised light can be linearly polarised by reflection from a transparent glass surface.

State the condition under which a large magnification can be achieved in an astronomical telescope.

The magnetic field through a circular loop of wire 12 cm in radius and 8.5 Ω resistance, changes with time as shown in the figure. The magnetic field is perpendicular to the plane of the loop. Calculate the induced current in the loop and plot it as a function of time.

The wavelength λ of a photon and the de-Broglie wavelength of an electron have the same value. Show that energy of a photon in (2λmc/h) times the kinetic energy of electron; where m, c and h have their usual meaning.

State Kirchhoff's rules and explain on what basis they are justified.

Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of (11/3) Ω?

Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of  (11/5) Ω?

Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of 6 Ω?

Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of  (6/11) Ω?

Determine the equivalent resistance of networks shown in Fig.

Determine the equivalent resistance of networks shown in Fig.

Draw a ray diagram showing the image formation of a distant object by a refracting telescope ?

Write the two important factors considered to increase the magnifying power?

Describe briefly the two main limitations and explain how far these can be minimized in a reflecting telescope ?

"A telescope resolves whereas a microscope magnifies." Justify this statement ?

Describe briefly how the Davisson-Germer experiment demonstrated the wave nature of electrons.

Draw a labelled ray diagram of an astronomical telescope to show the image formation of a distant object. Write the main considerations required in selecting the objective and eyepiece lenses in order to have large magnifying power and high resolution of the telescope.

What does a polaroid consist of? How does it produce a linearly polarised light?

Why photoelectric effect cannot be explained on the basis of wave nature of light? Give reasons.

State Kirchhoff's rules for an electric network. Using Kirchhoff's rules, obtain the balance condition in terms of the resistances of four arms of Wheatstone bridge.