CBSE Physics Model Question Paper- V
1. What is the difference between an ordinary electron and photoelectron?
Answer
2. What is the function of starter in an electric motor?
Answer
3. Give definition of ampere in terms of two wires carrying current placed at some distance.
Answer
4. Define dipole moment in terms of torque experienced by it when placed in a unifoim magnetic field.
Answer
5. On a resistor, body is marked red, edge blue and dot green and ring golden. What is the value of resistance?
Answer
6. A capacitor blocks A.C., why?
Answer
7. What would have been the colour of the sky in the absence of atmosphere?
Answer
8. What are the units of conductance and conductivity?
Answer
9. Give truth table of diagram given here.
Image 
Answer
10. What are differences between Peltier effect and Joule effect?
Answer
11. What is unit of capacity of a cell? Explain in 2-3 lines its significance.
Answer
12. What is forbidden energy gap? What is its significance?
Answer
13. What is quantization of electric charge 7 Explain it by giving two examples.
Answer
14. Draw a set of three converging and a set of three diverging wave fronts.
Answer
15. An electron is describing a circle in a magnetic filed of 10-4 T. Calculate the frequency of revolution. Given the mass of electron = 9x 10-31 kg and charge on the electron -
1-6 X 10-19 C.
Answer
16. Declination at a place is 2°E. Through what angle should the ship be steered with respect to north of the needle so as tq go towards west.
Answer
17. What is Ampere’s circuital law? Derive it.
Answer
18. If specific charge of proton is 9.6 X 107 C kg-1, find the specific charge of a-particle.
Answer
19. Twelve wires each of 4 Q resistance are joined to form a skelton cube. Find the resistance across diagonally opposite corners of the cube.
Answer
20. Draw a graph showing as to how the stopping potential varies with the frequency of the incident radiations. What does the slope of the line with frequency axis indicate?
Answer
21. Derive a relation between the distance of object, distance of image, radius of curvature and refracting index for a convex refracting surface when a light is going from an optically denser to an optically rarer medium.
Answer
22. What is Lenz’s law? Show that it is in accordance with law of conservation of energy.
Answer
23. The phase difference between two waves reaching a point is Π /2. What is the resultant amplitude if the individual amplitudes are 2 and 4 mm respectively?
Answer
24. What is radioactive fall out? What is its effect on human race?
Answer
25. What are carrier waves? How can these be produced by a transistor?
Answer
26. What are different types of spectra? How can the constitution of the material of the sun’s chromosphere be known from the study of sun’s spectra.
Answer
27. A P.D. of V is applied across a conductor of length L, diamater D. How are the electric field E, the drift velocity vd and resistance R affected when (i) V is doubled ; (ii) L is doubled, (iii) D is doubled ?
Answer
28. What is a solenoid? Derive an expression for the magnetic field inside the solenoid and at its edge.
OR
A double slit is illuminated by light of wavelength 6000A. The slits are 0 .1 cm apart and screen is placed 1 m away. Calculate (i) the angular positions of 10th maxima in radians (ii) separation of two adjascent minima.
Answer
29. Describe tangent galvanometer. Give its theory and working. What are its disadvantages over moving coil galvanometer?
Answer
30. Two small spheres of mass m, charge q each are suspended from a point by insulated threads each of length / and negligible mass. If 0 is the angle each makes with vertical when equilibrium
has been established. Show that q2 = 16Π mgl2 sin2θ tan θ.
Answer