PHYSICS

CLASS - XI

General Instructions

1. Questions from question no. 1-4 carry 1 marks each, 5-12 carry 2 marks each, 13-27 carry 3 marks each and 28-30 carry 5 marks each.
2. There is no overall choice but one choice is given in 2 marks question, two choice in 3 marks question and all three choices in five marks question
3. You may use the following physical constant where ever necessary:

Speed of light <math>C = 3 \times 10^8 \text{ ms}^{-1}</math>

Gravitational constant G = 6.6 x 10^-11 NM² Kg^-2

Gas constant R = <math>8.314 \text{ J Mol}^{-1} \text{ k}^{-1}</math>

Mass of electron = 9.110 x 10^-31 Kg

Mechanical equivalent of heat = 4.185 J Cal-1

Standard atmospheric pressure = 1.013 × 10⁵ Pa

Absolute zero 0K = -273.15°C

Acceleration due to gravity = 9.8 Ms^-2

Use of calculator is not permitted. However you may use log table, if re- quired. Draw neat labelled diagram wherever necessary to explain your answer.

1. A light body and heavy body have equal momentum, which one have greater kinetic energy?

What does speedometer of a car indicates?

Write down the dimensions of viscosity coefficient

1. Why do we use ball-bearings?
2. Physics

194

1. How errors are combined in following mathematical operations of physical quantities?

1. Subtraction

1. Draw the Velocity - Time graph for following cases when (i) Object is moving in positive direction with acceleration (ii) An object is under free fall.

Derive the necessary relation for safest velocity of an automobile on a banked road radius r and friction coefficient μ.

1. If variation of position with time t is given by <math>x = a + bt + ct^2</math>. Write the dimensions of a, b & c.
2. The forces whose magnitude is in the ratio of 3:5 give a resultant of 35 N. If the angle b/w them is 60°. Find the magnitude of each force.

1. What is an impulse? A ball coming towards a batsman with a certain velocity U. He deflects the ball by an angle Q and its velocity increases to
2. Draws A vector diagram to show initial momentum, find momentum and impulse.

In the given system of masses m₁ = 5 kg, and coefficient of friction for each constant is 0.2. Calculate the mass m2, if m1 is sliding down with an acceleration of 2 ms-2. What will be the tension in the string?

The radius and length of a solid cylinder is measured as R = (10.0 +/- 02) cm, I = (20.0 + /- 0.5) cm. Calculate the volume and surface area of the cylinder and error in them.

A bomb is exploded into three fragments of mass 1:2:3. The fragment having lighter masses move with a speed of 40 m/s in mutually perpendicular to each other. Calculate the velocity of the third fragment.

1. If <math>\vec{A}(2\hat{i} + 2\hat{j} + 2\hat{k})</math> and <math>\vec{B} = (3\hat{i} + 4\hat{j})</math>. Determine the vector having same magnitude as B and parallel to A.
2. Physics

195