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

An electric dipole of length 2 cm is placed at an angle of 30° with an electric field 2 × 10⁵ N/C. If the dipole experiences a torque of 8 × 10^-3 Nm, the magnitude of either charge of the dipole is ______.

An infinite line charge produces a field of 9 × 10⁴ N/C at a distance of 2 cm. Calculate the linear charge density.

Draw a schematic ray diagram of a reflecting telescope showing how rays coming from a distant object are received at the eyepiece.

Draw a labeled ray diagram to obtain the real image formed by an astronomical telescope in normal adjustment position. Define its magnifying power.

Three identical polaroid sheets P₁, P₂ and P₃ are oriented so that the pass axis of P₂ and P₃ are inclined at angles of 60° and 90° respectively with the pass axis of P₁. A monochromatic source S of unpolarised light of intensity I₀ is kept in front of the polaroid sheet P₁ as shown in the figure. Determine the intensities of light as observed by the observer at O, when polaroid P₃ is rotated with respect to P₂ at angles θ = 30° and 60°.

State the two Kirchhoff’s rules used in electric networks. How are there rules justified?

What dose a polaroid consist of?

Show, using a simple polaroid, that light waves are transverse in nature. Intensity of light coming out of a polaroid does not change irrespective of the orientation of the pass axis of the polaroid. Explain why.

State and explain Gauss’s law.

Why does an unpolarised light incident on a polaroid get linearly polarised ?

A proton and an α-particle have the same de-Broglie wavelength Determine the ratio of  their speeds.

Find an expression for intensity of transmitted light when a polaroid sheet is rotated between two crossed polaroids. In which position of the polaroid sheet will the transmitted intensity be maximum?

Use Kirchhoff's rules to obtain conditions for the balance condition in a Wheatstone bridge.

How does one demonstrate, using a suitable diagram, that unpolarised light when passed through a Polaroid gets polarised?

A beam of unpolarised light is incident on a glass-air interface. Show, using a suitable ray diagram, that light reflected from the interface is totally polarised, when μ = tan i_B, where μ is the refractive index of glass with respect to air and i_B is the Brewster's angle.

Show, with the help of a diagram, how unpolarised sunlight gets polarised due to scattering.

Two polaroids P₁ and P₂ are placed with their pass axes perpendicular to each other. An unpolarised light of intensity I_o is incident on P₁. A third polaroid P₃ is kept in between P₁ and P₂ such that its pass axis makes an angle of 45° with that of P₁. Determine the intensity of light transmitted through P₁, P₂ and P₃

Using the phenomenon of polarisation, show how the transverse nature of light can be demonstrated.

Two polaroids P₁ and P₂ are placed with their pass axes perpendicular to each other. An unpolarised light of intensity I₀ is incident on P₁. A third polaroid P₃ is kept in between P₁ and P₂ such that its pass axis makes an angle of 30° with that of P₁. Determine the intensity of light transmitted through P₁, P₂ and P₃

Show, via a suitable diagram, how unpolarised light can be polarised by reflection.