JAC Class 12 Physics Question Paper 2015 with Solution

About this paper

This is the Jharkhand Academic Council (JAC) Class 12 Physics paper from the 2015 board examination, with an answer under each question. Group A is 15 one-mark objective parts on electric field, capacitors, a potentiometer, alternating current, the spectrum, the electron-volt and logic gates. Group B has eight short questions, and the printed instruction gives them two marks each. Group C has eight questions, from the torque on a dipole and drift velocity to rectifiers and modulation, and Group D has three long questions. The toroid question has a cyclotron as its alternative, and the mutual-inductance question has reactance, impedance and a choke coil. A total for the paper and the time are not printed.

Exam

JAC Class 12

Subject

Physics

Year

2015

Questions

20

Pages

5

Answers included

Yes

Paper pattern

• Group A

  Question 1 with 15 objective parts

• Group B

  Questions 2–9; the instruction says eight questions of two marks each

• Group C

  Questions 10–17

• Group D

  Questions 18–20, with an alternative to the toroid question and to the mutual-inductance question

Topics covered

• Electrostatics and electric dipoles
• Current electricity and potentiometer
• Magnetism and Ampere's law
• Electromagnetic induction and transformers
• Alternating current and choke coils
• Ray optics, dispersion and lenses
• Wave optics and coherence
• Photoelectric effect and the Rydberg constant
• Radioactivity
• Semiconductors, LEDs and rectifiers
• Communication and modulation

Questions from this paper

1. What is electric flux? Give its unit.
2. The core of a transformer is laminated. Why?
3. What is drift velocity? Establish Ohm's law for a conductor using the idea of drift velocity.
4. Find the energy of a yellow photon in electron-volts. The wavelength of yellow light is 6000 Å.
5. State Ampere's circuital law. Find the magnetic field at a point inside a current-carrying toroid, and hence inside a long solenoid.
6. Explain why Lenz's law is in accordance with the law of conservation of energy, and find the mutual inductance of two long coaxial solenoids.