CBSE Physics Model Practice Question Paper- 6
1. Name the physical quantity which has Am2 as unit for measurement.
Answer
2. Differentiate between ionization energy and work function of a metal.
Answer
3. Can we accelerate a charge in a magnetic field?
Answer
4. Define voltage sensitivity of a galvanometer.
Answer
5. Draw the symbol for a cell and show the sense of e.m.f. in it.
Answer
6. Two protons of a nucleus are 6.0 x 10-6 m apart calculate their mutual potential energy.
Answer
7. State one reason why magnetic forces are stronger than the electrostatic force in current carrying conductors.
Answer
8. What is approximate half life of a proton?
Answer
9. How many spectral lines are emitted by a hydrogen atom that is excited to nth stationary state.
Answer
10. Derive an expression for the current flowing in a conductor in terms of the drift velocity of charge carriers.
Answer
11. A steel wire of length / has a magnetic moment M. It is bent into a semicircular arc. Will the magnetic moment change? What is the new value?
Answer
12. What are slow neutrons? Why heavy water (D2O) is used as a moderator to slow down neutrons?
Answer
13. Two point charges q1 and q2 are situated at points A and B. The charge q1 is surrounded by a metallic shell. What is the force on q1? What is the force on q2?
Answer
14. In the circuit shown if G reads zero, what is the value of R?
Image 
Answer
15. Find an expression the time period of an oscillating magnetic needle in a uniform magnetic field.
Answer
16. What are the currents in 1 Ω coil and 5 Ω resistance at t = 0 when the switch is just pressed ?
Image
Answer
17. With the use of a suitable diagram show how the sun even below the horizon can be seen sometimes.
Answer
18. If in a Rutherford’s experiment the α particle scattered at 90° be 28 per minute. Find out the number of particles scattered at 120°?
Answer
19. What is the principle of measurement of internal resistance of a cell? When the resistance between a and b is 36 Ω and the cell e has emf 1.5 V, there is no current in the galvanometer. When this cell is replaced by an unknown emf, the resistance between a and b is 48 Ω for no current in the galvanometer. What is the value of unknown emf?
Image
Answer
20. Draw the logic symbol of NAND gate. Describe its realisation.
Answer
21. Derive a relation between polarising angle and critical angle of a transparent substance drawing suitable illustrative labelled diagram.
Answer
22. What is a superior planet? How its distance from sun be determined?
Answer
23. State Joule’s law for dissipation of heat in a conductor. Why fuse wire used for heavy current must be thicker than that used for small currents?
Answer
24. The power of a lens is 3 D. When immersed in a liquid its power is- 2 D. If the R.I. lens is 3/2. What is the R.I of the liquid?
Answer
25. What are limitations of a transistor amplifier as a cut-off transistor and as a saturated transistor?
Answer
26. What is the angle of deviation θ if the charged particle of mass m and charge q enters the magnetic field perpendicular to its velocity v. The width dof the region of the magnetic field is smaller than (i) mv/2qb (ii) 2 mv /pb (iii) mv/ qb .
Image
Answer
27. The intensity of light due to one slit in a Young’s double slit experiment is twice the intensity of light due to the other slit. What is the ratio of maximum intensity to minimum intensity in the interference fringe pattern?
Answer
28. How a rainbow is seen during the rainy season? Illustrate your answer with suitable diagrams.
Find the condition for formation of first dark ring due to light diffraction by a circular aperture of diameter d.
Answer
29. What are the relative merits of common base, common emitter and common collector transistor amplifiers? How does the voltage gain of an amplifier differ from its current gain?
Answer
30. Why the plates in Millikans oil drop experiment be kept exactly parallel and horizontal? Derive an expression for the radius of an oil drop falling with a terminal velocity u. Use this expression to find e when the drop moves upward with a terminal velocity v.
Answer