NEB MODEL QUESTION FOR PHYSICS
Time : 3 hrs
Full Marks: 75
Pass marks: 27
Q.1. Answer in brief, any SIX questions. [2 X 6 = 12]
(a) What is the difference between accurate and precise measurements?(b) A ball having a momentum P hits a bat and its momentum becomes –P. What is the change in the momentum of the ball?
Q.2. Answer in brief, any TWO questions . [2 X 2 = 4]
(a) Why are two thin blankets warmer than a single blanket of double the thickness?
Q.3. Answer in brief, any ONE question : [1 X 2 = 2]
(a) Can a convex mirror ever from a real image? If so, explain with a diagram.
Q.4. Answer in brief, any ONE question : [2 X 1 = 2]
(a) A man inside an insulated metallic cage does not receive a shock when the cage is highly charged. Explain.
Q.5. Answer any THREE questions : [4 X 3 = 12]
(a) State the principle of conservation of linear momentum. How does Newton’s third law of motion lead to the principle of conservation of linear momentum?
Q.6. Answer any TWO questions : [4 X 2 = 8]
(a) Define specific latent heat of fusion of a solid. Develop an expression for the latent heat of fusion of ice.
Q.7. Answer any ONE question : [ 4 X 1 = 4 ]
(a) Define the power of a lens. Derive the formula for the effective power of two thin lenses in contact.
Q.8. Answer any ONE question : [4 X 1 = 4]
(a) State Gauss law. Apply it to obtain an expression for the electric field outside the charged special conductor.
Q.9. Solve any Three numerical questions : [4 X 3 = 12]
(a) A ballet dancer spins with 2.4 revs/s with her arms outstretched when the moment of inertia about the axis of rotation is I. With her arms folded, the moment of inertia about the same axis becomes 0.6 I. Calculate the new rate of spin.
Q.10. Solve any TWO questions : [4 X 2 = 8]
(a) A ball of copper of specific heat capacity 400 Jkg-1K-1 weighting 400 gm is transferred from a furnace to 1 Kg of water at 20oC. The temperature of the water rises to 50oC. What is the initial temperature of the ball?
Q.11. A microscope is focused on the upper surface of a glass plate. A second plate is then placed over the first. In order to focus on the bottom surface of the second plate, the microscope must be raised 1 mm. In order to focus on the upper surface, it must be raised 2 mm farther. Find the index of the retardation of the second plate.Q.12. Two-point charges +1 µC is placed at a distance of 0.12 m apart. Determine the point on the line joining two charges where net forces acting on the positive charges is zero.
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What is Q1 (e) ?
Ohh I got it:
Q: Why is sand thrown on roads covered with snow?A: Sand is thrown on roads covered with snow because when the tracks/ roads are covered with snow there is a reduction of friction between the tires of the vehicles and the road and during this situation it is dangerous to drive. when sand is thrown on the roads covered with snow then the friction increases between the road and the tire of the vehicle, and safe driving is possible.