ISC (Science) ISC Class 12 - CISCE Important Questions for Physics (Theory)

Identify the part of the electromagnetic spectrum which is suitable for radar system used in aircraft navigation.

State how a moving coil galvanometer can be converted into an ammeter.

What is mass defect?

State Gauss’ Law.

Show that intensity of electric field at a point in broadside position of an electric dipole is given by:

E = `(1/(4 pi epsilon_0)) p/((r^2 + l^2)^(3//2))`

Where the terms have their usual meaning.

Arrangement of an oxygen ion and two hydrogen ions in a water molecule is shown in the figure below.

Calculate the electric dipole moment of a water molecule. Express your answer in terms of e (charge on hydrogen ions), l and θ.

Draw a labelled circuit diagram of a potentiometer to measure the internal resistance ‘r’ of a cell. Write the working formula (derivation is not required). 

Draw a labelled circuit diagram of a potentiometer to compare emfs of two cells. Write the working formula (Derivation not required).

Calculate the shortest wavelength of electromagnetic radiation present in Balmer series of hydrogen spectrum.

What happens when an electron collides with a positron?

Name the principle on the basis of which optical fibres work.

Using Huygen’s wave theory of light, show that the angle of incidence is equal to the angle of reflection. Draw a neat and labelled diagram.

On the basis of Bohr's theory, derive an expression for the radius of the n^th orbit of an electron of the hydrogen atom.

Write one balanced equation to show Nuclear fission

Why nuclear fusion reaction is also called thermo-nuclear reaction?

What is ‘Pair production’?

Draw solar cell V-I characteristics.

A short electric dipole (which consists of two point charges, +q and -q) is placed at the centre 0 and inside a large cube (ABCDEFGH) of length L, as shown in Figure 1. The electric flux, emanating through the cube is:

a) `q"/"4piin_9L`

b) zero

c) `q"/"2piin_0L`

d) `q"/"3piin_0L`

Derive an expression for the intensity of electric field at a point in broadside position or on [4)
an equatorial line of an electric dipole.

 A closed surface in vacuum encloses charges –q and +3q. The total electric flux emerging out of the surface is :