ISC (Science) ISC Class 12 - CISCE Question Bank Solutions for Physics (Theory)

A hollow sphere of radius R has a point charge q at its centre. Electric flux emanating from the sphere is X. How will the electric flux change, if at all, when charge q is replaced by an electric dipole?

The figure below shows a circuit containing an ammeter A, a galvanometer G and a plug key K. When the key is closed:

A galvanometer of resistance 100 Ω gives a full-scale deflection for a potential difference of 200 mV.

1. What must be the resistance connected to convert the galvanometer into an ammeter of the range 0-200 mA?
2. Determine resistance of the ammeter.

A rectangular loop of area 5m2, has 50 turns and carries a current of 1A. It is hold in a uniform magnetic field of 0.1T, at an angle of 30°. Calculate the torque experienced by the coil. 

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

State Gauss’ Law.

ε₁ and ε₂ are two batteries having emf of 34V and 10V respectively and internal resistance of 1Ω and 2Ω respectively. They are connected as shown in the figure below. Using Kirchhoff’s Laws of electrical networks, calculate the currents I₁ and I₂.

On which conservation principle is Kirchoff's Second Law of electrical networks based?

In the circuit shown in the figure below, E₁ and E₂ are two cells having emfs 2 V and 3 V respectively, and negligible internal resistance. Applying Kirchhoff’s laws of electrical networks, find the values of currents l₁ and I₂.

In the circuit shown in Figure below, E₁ and E₂ are batteries having emfs of 25V and 26V. They have an internal resistance of 1 Ω and 5 Ω respectively. Applying Kirchhoff’s laws of electrical networks, calculate the currents I₁ and I₂.

What is meant by the statement: "Relative permittivity of water is 81"?

The figure below shows two batteries, E1 and E2, having emfs of 18V and 10V and internal resistances of 1 Ω and 2 Ω, respectively. W₁, W₂ and W₃ are uniform metallic wires AC, FD and BE having resistances of 8 Ω, 6 Ω and 10 Ω respectively. B and E are midpoints of the wires W₁ and W₂. Using Kirchhoff's laws of electrical circuits, calculate the current flowing in the wire W₃:

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

An electrical bulb is marked 200V, 100W. Calculate the electrical resistance of its filament. If five such
bulbs are connected in series to a 200V supply, how much current will flow through them?

State Moseley's law

With the help of a labelled diagram, show that the balancing condition of a Wheatstone bridge is

`R_1/R_2 = R_3/R_4` where the terms have their usual meaning.

In a conductor 6.25 × `10^16` electrons flow from its end A to B in 2 s. Find the current flowing through the conductor (e = 1.6 × `10^-19` C)

Obtain the balancing  condition for the Wheatstone bridge arrangements as shown in Figure 4 below:

State the name and the range of wavelength of the invisible electromagnetic waves beyond the red end of the visible spectrum.

Name three radiations and their wavelength range which are invisible and beyond the violet end of the visible spectrum.