(Download) CBSE: Class XII APPLIED Physics Question Paper - 2020

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Question Papers For Board Examinations 2020

Class – XII

Subject –APPLIED Physics

Subject :- APPLIED Physics
Class : XII
Year : 2020

1. (a) Define electric field intensity. Give its SI unit. Write the formula for electric field intensity due to a point charge. Calculate the electric field intensity at a distance of 50 cm from a charge of 50 C. 5

(b) What is a capacitor ? Derive a formula for the energy stored in a capacitor. 5
OR
Draw a figure showing the combination of three capacitors in series. Write the formula for the net capacitance when three capacitors are connected in series. Three capacitors of 2 F, 3 F and 6 F are connected in series. Find the net capacitance. 5

2. (a) Define magnetic field. Write the SI unit of magnetic field intensity.
Write the formula for the magnetic field intensity due to a straight current-carrying conductor. What is the value of the magnetic field at the surface of the conductor ? 5
(b) What are the factors that affect the force on a charge moving in a magnetic field ? Write the formula for the force. State the cases when the charge will experience (i) maximum, and (ii) minimum force. 5
OR
Define the terms Magnetic flux density and Permeability. Write their SI units. Write the name of a substance having large permeability. 5
(c) Derive an expression for the magnetic field intensity at the centre of a current-carrying circular coil.

3. (a) Define nuclear fission and nuclear fusion. Give three differences between them. 5
(b) What are radio-isotopes ? Write the name of two radio-iostopes and write one use of each. 5
OR
What are radiation hazards ? Name two radiation hazards. How can we protect ourselves from radiation hazards ? 5
(c) Explain the principle, construction and working of a nuclear reactor. 5
4. (a) What are semiconductors ? Give the atomic structure of Ge and Si.
How is the conductivity of semiconductors affected by rise in temperature ? 5
(b) Draw the symbol of p-n junction. Draw a circuit diagram of p-n junction in forward biasing. Explain the working of a p-n junction in forward biasing. 5 OR
What is a rectifier ? Explain the working of a p-n junction as a full-wave rectifier. 5
(c) Draw a symbol of an n-p-n transistor. Draw a circuit diagram of n-p-n transistor with proper biasing and explain transistor action. 5