CBSE Physics Model Question Paper- VII
1. What is the absorption spectrum?
Answer
2. What is Bohr magneton?
Answer
3. Define relative permittivity. What substance has maximum relative permittivity?
Answer
4. A resistor has white, grey, red and golden lines. What is its resistance?
Answer
5. What is the force acting on a charge of 5C moving with a velocity of 20 ms-1 in the direction opposite to the field of strength 4T?
Answer
6. What is the role of back e.m.f. in d.c. motor?
Answer
7. What type of material is used for making permanent magnets?
Answer
8. What are radio-isotopes?
Answer
9. What is terminal F.D. of a cell? How is it related to e.m.f. of a cell?
Answer
10. A proton and an a-particle enters a uniform magnetic field perpendicularly with the same speed. How many times is the time period of the a-particie is than that of proton?
Answer
11. What is self inductance? Define coefficient of self inductance. Give its SI unit.
Answer
12. A lens of glass of refractive index 1 -50 is immersed in water of refractive index 1 - 33. Compare the focal length of lens in air to that in water.
Answer
13. How will you define nuclear radius? Determine the density of a nucleus (approximately).
Answer
14. What gate does the following Boolean relation represent A. B + A. B? Give its truth table.
Answer
15. Light from a lamp falls on a wooden table but no photoelectrons emitted from it but when it falls on an alkali metals, they are emitted. Why so? What is work function and how is it related to frequency?
Answer
16- What is mass defect?
Answer
17- Distinguish between electric and magnetic field.
Answer
18. You are having three resistors each of value R. How will you connect these to obtain a total resistance of 3 R/2? Show this by drawing suitable diagram.
Answer
19. What is pure spectrum? How can it be produced in laboratory?
Answer
20. Deduce the conditions of constructive and destructive interference.
Answer
21. How can a transistor be used as an oscillator? What is meant by feedbeck?
Answer
22. A circuit containing a pure resistor of 40 Ω is fed by a 200 V, 50 Hz A.C. mains. The current is reduced to half of its value when (i) a pure inductor, (ii) pure capacitor is introduced in series with resistor. Find the value of inductance and capacitance.
Answer
23. A beam of electron is moving parallel to a beam of protons. What do you predict about their behaviour under different conditions? Explain by quoting the relations used.
Answer
24. What is thermoelectric power? Show that it is independent of temperature of cold junction. How is thermoelectric power and neutral temperature related?
Answer
25. An electron and a proton are possessing the same amount of K.E. Which of the two have greater de-Broglie wavelength? Justify your answer,
Answer
26. Draw neat diagram of a telescope. Find its magnifying power. What is resolving power of a telescope? On what factors does it depend?
Answer
27. What are radioactive tracers? Give its uses in agriculture and industries.
Answer
28. Describe principle, construction and working of an A.C. dynamo.
What is diffraction? What are its types? Explain the diffraction at a single slit.
Answer
29. What are amplifiers? Describe the best PNF amplifier. Why is it best? To what use ampt are put to?
Answer
30. A proton falls vertically downwards through a distance of 2 cm in a uniform electric field o magnitude 3.34 x 103 NC-1. Calculate
(a) Acceleration of proton falling down.
(b) Time taken by proton to fall through a distance of 2 cm and
© The direction of electric field.
Answer