BLUE PRINT

SUB: PHYSICS CLASS: XI

TIME: 03 HOURS MAX. MARKS: 70

S.NO.

NAME OF THE CHAPTER

VSA

(1M)

SA-1

(2M)

SA-2

(3M)

VBQ

(4M)

LA

(5M)

TOTAL (70)

1.

PHYSICAL WORLD

1(1)

1(2)

2(3)

2.

UNITS AND MEASUREMENTS

1(2)

1(3)

2(5)

3.

MOTION IN STRAIGHT LINE

1(2)

1(3)

2(5)

4.

MOTION IN A PLANE

1(3)

1(4)

2(7)

5.

LAWS OF MOTION

1(3)

1(5)

2(8)

6.

WORK AND ENERGY

1(1)

1(5)

2(6)

7

GRAVITATIONS

1(2)

1(3)

3(5)

8

SYSTEM OF PARTICLE AND ROTATION MOTION

1(2)

1(3)

2(5)

9

MECH. PROPERTIES OF SOLID

1(1)

1(3)

2(4)

10

MECH. PROPERTIES OF FLUID

1(3)

1(3)

11

THERMAL PROPETIES OF MATTER

1(1)

1(3)

2(4)

12

KTG

1(1)

1(3)

1(4)

13

THERMODYNAMICS

1(3)

1(3)

14

OSCILLATION

1(5)

1(5)

15

WAVE MORION

1(3)

1(3)

TOTAL

5(5)

5(10)

12(36)

1(4)

3(15)

26(70)

SAMPLE QUESTION PAPER

PHYSICS CLASS -11

Time: Three HoursMaximum Marks: 70

General Instructions:-

(a)All questions are compulsory.

(b)There are 30 questions in total. Questions 1 to 8 carry one mark each, questions 9 to 18 carry two marks each, questions 19 to 27 carry three marks each and questions 28 to 30 carry five marks each.

(c)There is no overall choice. However, an internal choice has been provided in one question of two marks, one question of three marks and all three questions of five marks each. You have to attempt only one of the given choices in such questions.

(d)Use of calculator is not permitted.

(e)You may use the following physical constants wherever necessary.

1. Why we use a platinum iridium alloy in making prototype meter and

Kilogram?

(1)

2. Define coefficient of restitution or coefficient of resilience.

(1)

3. Radius of gyration is a constant quantity.

(1)

4. Why is ploughing of fields essential?

(1)

5. What is Magnus effect?

(1)

6. The length of the rod as measured in an experiment was found to be 3.23m, 3.25 m, 3.27

m, 3.22. Find the absolute error.(2)

7. There is a bug who moves from point A to point B and then finally to C in 5 seconds. Are the speed and velocity of the bug different?

(2)

8. Two wooden blocks A and B are connected to a chord, passing through a frictionless pulley. Block A is pushed to the left on a surface by a horizontal force. Draw the free body diagram of both the blocks. (2)

9. Explain that gravitational force is a conservative force.

(2)

10. Name a polar satellite. State its uses.

(2)

11. If the kinetic energy of one mole of an ideal gas is E=3/2 RT, what will be its Cp?(3)

12. In an experiment to find the speed of waves in a rope, a standing wave pattern is established as shown in diagram below. The vibrating end of rope makes 90 vibrations per minute. Find the speed of the wave?

(3)

13 Two point masses of 3 Kg and 2 Kg are attached at the two ends of a horizontal spring with spring constant k=200Nm-m. Find the natural frequency of vibration of the system.(3)

14. If a body A of mass M is thrown with velocity u at an angle 300 with the horizontal and another body B is of the same mass be projected with the same velocity at angle 600 to the horizontal, then prove that the ratio of horizontal ranges will be 1:1 and that of maximum height will be 1:3. (3)

15. Calculate the recoil velocity V of the gun of mass M when a bullet of mass m is fired with a horizontal velocity v.(3)

16. Derive equation for loss of kinetic energy in case of a completely inelastic

Collision in one dimension?(3)

17. Consider two bodies X and Y with mass m1 and m2 separated by distance r meters. Suppose mass of X is doubled and mass of Y is tripled also the distance between them is doubled. Find the ratio of the gravitational force before and after changing the masses and distance. (3)

18. What are thermal radiations? Give some of its basic characteristics.(3)

19. State the law of equipartition of energy. Show that the ratio of specific heat at constant pressure to specific heat at constant volume is 7/5 for a

rigid diatomic molecule.(3)

20. If the r.m.s speed of oxygen at NTP is x m/s. If the gas is heated at constant pressure till its volume is four fold, what will be its final temperature

and r.m.s speed?(3)

21. State and prove Work-energy theorem.(3)

22. The circular track of radius 100 m is banked at an angle of 30. If the coefficient of friction between the wheels of a car and the road is 0.5, then what is the (i) Optimum speed of the car to avoid wear and tear on its tires, and (ii) maximum permissible speed to avoid slipping? (3)

23. Suraj went to Big Bazaar to purchase certain goods .There he noticed an old lady struggling with her shopping. Immediately he showed her the lift and explained to her how it carries the load from one floor to the next. Even then the Old lady was not convinced. Then Suraj took her in the lift and showed her how to operate it. That old lady was very happy. a). What values does Suraj possess? b). A man of mass 80 kg stands on a weighing machine in a lift which is moving (i) upwards with uniform speed of 10 m/s. (ii) downwards with a uniform acceleration of 5 m/s2 (iii) upwards with a uniform acceleration of 5 m/s2 What would be the reading on the scale in each case? (4)

24. A fighter plane flying horizontally at an altitude of 1.5 km with speed 720 km/h passes directly overhead an anti-aircraft gun. At what angle from the vertical should the gun be fired for the shell with muzzle speed 600 m s1 to hit the plane? At what minimum altitude should the pilot fly the plane to avoid being hit? (Take g = 10 m s2).(5)

OR

A cyclist is riding with a speed of 27 km/h. As he approaches a circular turn on the road of radius 80 m, he applies brakes and reduces his speed at the constant rate of 0.50 m/s every second. What is the magnitude and direction of the net acceleration of the cyclist on the circular turn? (5) OR

25. A solid disc and a ring, both of radius 10 cm are placed on a horizontal table simultaneously, with initial angular speed equal to 10 rad s-1. Which of the two will start to roll earlier? The co-efficient of kinetic friction is k =0.2.(5)

OR

Read each statement below carefully, and state, with reasons, if it is true or false;

(a) During rolling, the force of friction acts in the same direction as the direction of motion of the CM of the body.

(b) The instantaneous speed of the point of contact during rolling is zero.

(c) The instantaneous acceleration of the point of contact during rolling is zero.

(d) For perfect rolling motion, work done against friction is zero.

(e) A wheel moving down a perfectly frictionless inclined plane will undergo

slipping (not rolling) motion.(5)

26 (a) What is the largest average velocity of blood flow in an artery of radius 2 103 m if the flow must remain laminar? (b) What is the corresponding flow rate? (Take viscosity of blood to be 2.084 103 Pa s). (5)

OR

In Millikans oil drop experiment, what is the terminal speed of an uncharged drop of radius 2.0 105 m and density 1.2 103 kg m3? Take the viscosity of air at the temperature of the experiment to be 1.8 105 Pa s. How much is the viscous force on the drop at that speed? Neglect buoyancy of the drop

due to air.(5)

SOLUTION

Ans1. The alloy is least affected by temperatures variations. It is non-corrosive and so does not wear out easily.(1)

Ans2. Coefficient of restitution is defined as the ratio of relative velocity of separation of the two bodies after collision to the relative velocity of

approach before collision. It is denoted by e.(1)

Ans3. No. Radius of gyration depends on axis of rotation and distribution of mass.(1)

Ans4. Ploughing of fields is essential as ploughing breaks the fine capillaries in the soil hence saving the loss of excess water which rises in the capillaries

and evaporates.(1)

Ans5. When a ball is thrown and given a spin, then the path of the ball is curved. The velocity of air above the ball relative is large and below it is small. This difference in the velocities of air results in the pressure difference between the lower and upper faces and this provides a upward force on the ball. This dynamic lift due to spinning is called Magnus effect. (1)

Ans6. The average length of the rod is: 12.99/4 = 3.247 = 3.25 (Rounding off to two decimal points)

(1)

Hence, the absolute possible error in the sum of two quantities is equal to the sum of the absolute errors in the individual quantities.(1)

Ans7. Physically, speed and velocity are different in the sense that the former is scalar, whereas the latter is a vector.

However, in terms of magnitude, in this case, both are equal.

Magnitude of velocity = speed = (20+5)/5 = 11 ms-1

This is because the bug happens to move along a straight line and does not turn back, in other words, does not change direction during its travel from A to C.

Ans8. Free body diagram of block A

Forces on block A are:

(i) WA = Weight of the block, acting downward

(ii) nA = Normal reaction force from surface, acting vertically upward.

(iii) T = Tension of chord

(v) f = Frictional force, acting against the applied force

Free body diagram of Forces on block B are:

(1)

(iv) Fapplied = Applied force

T = Tension in chord, acting vertically upward

WB = Weight of the body, acting vertically downward

(1)

Ans12. If a body of mass m is released from the top of a smooth inclined plane of height h, it gains speed at the bottom given by

V2 - 02= 2gh or

(1) Kinetic energy acquired by the body at the bottom of inclined plane is

Ans9. Clearly the work done by the gravitational force does not depend on the angle of inclination or path of the falling body. It depends on the initial and final position of the body. This proves that gravitational force is a

conservative force.

(1)

Ans10. Sea star is a polar satellite.

(1/2)

Polar satellites are used for

1. Getting cloud images,

2. Atmospheric data,

3. To detect the ozone hole.(1/2 for each point)

Ans11.

Ans12.

Ans13.

Ans14. We know that horizontal range and maximum heights are independent of the mass of bodies. Therefore

Horizontal range of body A,

(1/2) And for body B,

(1/2)

That is

(1/2)

Now maximum height for body A,

Ans15. We are given here,

Mass of the gun=M

Mass of the bullet=m

Velocity of the bullet=v

Recoil velocity of the gun=V

As initially both the bullet and gun are at rest, then applying principle of

Conservation of momentum, we get(1)

Total momentum of gun + bullet before firing= Total momentum of gun+ bullet after firing(1)

0= MV + mv

(1)

Ans16. Consider two massesand.Let the particle is moving with initial speedandbe at rest.

(1)

In case of an perfectly inelastic collision in one dimension,

Applying law of conservation of momentum, we get

where is the final velocity of the combined mass ( (+)).

The loss in kinetic energy on collision is

(1) This is a positive quantity.

Ans17.

Ans18.Thermal radiations are radiations emitted by everybody (that has temperature above 0 Kelvin) on account of its temperature. Thermal radiations are also called infra red radiations as their wavelength ranges from

8 x 10 -7 m to 4x 10-4 m.(1/2)

Basic characteristics of thermal radiations are

i. Thermal radiation requires no medium to propagate. They can travel through vacuum.

ii. Thermal radiations travel in straight lines with the speed of light.iii. They do not heat the intervening medium through which they pass.

iv. Their intensity varies inversely as the square of the distance from thesource.

v. Thermal radiations show the phenomena of interference, diffraction, reflection, refraction and polarization like light radiations.

(1/2 for each point)

Ans19. In equilibrium, the total energy is equally distributed in all possible energy modes, with each mode having an average energy equal to 1/2kT. This is the

law of equipartition of energy.(1)

A diatomic molecule that can be taken as a rigid rotator with 5 degrees of freedom: 3 translational and 2 rotational. Using the law of equipartition of energy the total internal energy of a mole of such a gas is given by

U = 5kT NA = 5RT (1)

2 2

Then molar specific heat at constant volume CV = 5/2R and molar specific heat at Constant pressure CP =7/2R

Hence = cp/cv =7/5

Ans20.

Ans21.

Work-energy theorem states that the work done on a particle by a resultant force is equal to the change in its kinetic energy.(1)

W =F ds.

W=F dsdt .dt(1)

W= Fvdt.

W = dKdt.dt

W= Dk

W = (K2 - K1)

Ans24.

Height of the fighter plane = 1.5 km = 1500 m

Speed of the fighter plane, v = 720 km/h = 200 m/s

Let be the angle with the vertical so that the shell hits the plane. The situation is shown in the given figure.

(1)

Muzzle velocity of the gun, u = 600 m/s

Time taken by the shell to hit the plane = t

Horizontal distance travelled by the shell = uxt

Distance travelled by the plane = vt

The shell hits the plane. Hence, these two distances must be equal.

uxt = vt(1)

(1)

In order to avoid being hit by the shell, the pilot must fly the plane at an altitude (H) higher than the maximum height achieved by the shell.

OR

Speed of the cyclist,

Radius of the circular turn, r = 80 m Centripetal acceleration is given as:

(1) The situation is shown in the given figure:

(1)

Suppose the cyclist begins cycling from point P and moves toward point Q. At point Q, he applies the breaks and decelerates the speed of the bicycle by 0.5 m/s2.

This acceleration is along the tangent at Q and opposite to the direction of motion of the cyclist.(1)

Since the angle between is 90, the resultant acceleration a is given by:

Ans25. Disc - Radii of the ring and the disc, r = 10 cm = 0.1 m

Initial angular speed, 0 =10 rad s1

Coefficient of kinetic friction, k = 0.2

Initial velocity of both the objects, u = 0

Motion of the two objects is caused by frictional force. As per Newtons second law of motion, we have frictional force, f = ma

k mg= ma

Where, a = Acceleration produced in the objects, m = Mass

a = kg (i)(1)

As per the first equation of motion, the final velocity of the objects can be

obtained as:v = u + at

= 0 + k gt

= k gt (ii)

The torque applied by the frictional force will act in perpendicularly outward direction and cause reduction in the initial angular speed.

Torque, = I

= Angular acceleration

x mgr = I

(1)

Using the first equation of rotational motion to obtain the final angular speed:

Rolling starts when linear velocity, v = r

(1)

Equating equations (ii) and (v), we get:

Since td > tr, the disc will start rolling before the ring.(1)

OR

(a) False; Frictional force acts opposite to the direction of motion of the centre of mass of a body. In the case of rolling, the direction of motion

of the center of mass is backward. Hence, frictional force acts in the forward

direction.(1)

(a) True; Rolling can be considered as the rotation of a body about an axis passing through the point of contact of the body with the ground. Hence, its

instantaneous speed is zero.(1)

(b) False; when a body is rolling, its instantaneous acceleration is not equal

to zero. It has some value.(1)

(c) True; when perfect rolling begins, the frictional force acting at the lowermost point becomes zero. Hence, the work done against friction is also

zero.(1)

(d) True; the rolling of a body occurs when a frictional force acts between the body and the surface. This frictional force provides the torque necessary for rolling. In the absence of a frictional force, the body slips from the inclined

plane under the effect of its own weight.(1)

26. (a) Radius of the artery, r = 2 103 m

Diameter of the artery, d = 2 2 103 m = 4 10 3 m(1/2)

Viscosity of blood,

Density of blood, = 1.06 103 kg/m3

Reynolds number for laminar flow, NR = 2000

The largest average velocity of blood is given by the relation:

(1/2)

(1/2)

(1)

Therefore, the largest average velocity of blood is 0.983 m/s.

(b) Flow rate is given by the relation:

R = r2 Vavg

(1)

(1)

Therefore, the corresponding flow rate is.(1/2)

OR

Terminal speed = 5.8 cm/s; Viscous force = 3.9 1010 N

Radius of the given uncharged drop, r = 2.0 105 m

Density of the uncharged drop, = 1.2 103 kg m3

Viscosity of air,

Density of air 0 can be taken as zero in order to neglect buoyancy of air.

Acceleration due to gravity, g = 9.8 m/s2(1)

Terminal velocity (v) is given by the relation:

Hence, the terminal speed of the drop is 5.8 cm s1.(1)

The viscous force on the drop is given by:

(1)

Hence, the viscous force on the drop is 3.9 1010 N.(1)