#### 11th Standard Physics English Medium Free Online Test 1 Mark Questions 2020 - Part Eight

11th Standard

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Physics

Time : 00:25:00 Hrs
Total Marks : 25

25 x 1 = 25
1. The term used to mention study of macroscopic system to microscopic constituents is

(a)

unification

(b)

macrocosm

(c)

reductionism

(d)

microcosm

2. In equation of motion S = ut+$1\over 2$kt2 the dimensional formula for K is______________

(a)

[L T-1]

(b)

[L T-2]

(c)

[T]

(d)

[L-1 T]

3. When a body undergoes an oblique projection, maximum range of it is:

(a)

$\frac{u^2}{g}$

(b)

$\frac{u}{g}$

(c)

$\frac{u^2}{g^2}$

(d)

$\frac{u^2}{2g}$

4. Two cars P and Qstart fun a point at the same time in a straight line and their positions are represented by Xp(t) = (at + bt2) and xQ(t) = (ft - ft2). At what time do the cars have the same velocity?

(a)

${a-f\over l+b}$

(b)

${a+f\over2(b-1)}$

(c)

${a+f\over2(l+b)}$

(d)

${f-a\over2(b-1)}$

5. A body is projected vertically upward with the velocity v=$3\hat{i}+4\hat{j} \ ms^{-1}$ The maximum height attained by the body is (g=10ms-2)

(a)

7 m

(b)

1.25m

(c)

8m

(d)

0.08m

6. Twelve forces each of magnitude 10N acting on' a body at an angle of 30° with other forces then their resultant is

(a)

10 N

(b)

120 N

(c)

$\frac{10}{\sqrt{3}}$

(d)

zero

7. A vehicle is moving along the positive x direction, if sudden brake is applied, then

(a)

frictional force acting on the vehicle is along negative x direction

(b)

frictional force acting on the vehicle is along positive x direction

(c)

no frictional force acts on the vehicle

(d)

frictional force acts in downward direction

8. Three forces F2, F2 & F3 are acting on a particle of mass m such that F2 & F3 are mutually perpendicular, then the particle remains stationary. If the force F1 is now removed, then the acceleration of the particle is

(a)

$\frac { { F }_{ 1 } }{ m }$

(b)

$\frac { { F }_{ 2 }{ F }_{ 3 } }{ mF }$

(c)

$\frac { { F }_{ 2 }-{ F }_{ 3 } }{ m }$

(d)

$\frac { { F }_{ 2 } }{ m }$

9. The force required to stop a moving object depends on its:

(a)

mass alone

(b)

velocity alone

(c)

mass or velocity

(d)

mass and velocity

10. If the tension in the cable of 1000 kg elevator is 1000 kg weight, then the elevator:

(a)

is accelerating upwards

(b)

is accelerating downwards

(c)

may be at rest or accelerating

(d)

may be at rest or in uniform motion

11. Which of the following is the dimension of coefficient of friction?

(a)

[MLT-2]

(b)

[M0L0T0]

(c)

[M2LT-2]

(d)

[M2LT]

12. A boy presses a book against the front wall such that the book does not move. The force of friction between the wall and the book is:

(a)

towards right

(b)

towards left

(c)

downwards

(d)

upwards

13. When a car is turning around a corner, the person sitting inside the car:

(a)

may fall down

(b)

experiences a force

(c)

experiences an inward force

(d)

experiences outward force

14. A lift is moving down with an acceleration of 4.9 ms-2. The percentage change in the weight of a person in the lift is

(a)

75%

(b)

50%

(c)

25%

(d)

12.5%

15. A bag of sand of mass 'm' is suspended by a rope. A bullet of mass $\left( \frac { m }{ 20 } \right)$ is fired at it with a velocity V and gets embedded in it. The final velocity of the bag is

(a)

$\frac { 21V }{ 20 }$

(b)

$\frac { V }{ 21 }$

(c)

$\frac { V }{ 20 }$

(d)

$\frac { 20 }{ 21 } V$

16. Two stones of masses m and 2m are whirled in horizontal circles, the heavier one in a radius $\frac { r }{ 3 }$ and the lighter one in radius r. The tangential speed of lighter stone is n times that of the value of heavier. stone when they experience same centripetal forces. The value of n is

(a)

4

(b)

1

(c)

2

(d)

3

17. A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 m/s. A bob is suspended from the roof of the car by a light wire of length 1.0 m. The angle made by the wire with the vertical is

(a)

$\frac { \pi }{ 3 }$

(b)

$\frac { \pi }{ 6 }$

(c)

$\frac { \pi }{ 4 }$

(d)

00

18. The mass of a lift is 2000 kg. When the tension in the supporting cable is 28000 N, then its acceleration is

(a)

4 m s-2 upwards

(b)

4 m s-2 downwards

(c)

14 m s-2 upwards

(d)

30 m s-2 downwards

19. A lift of mass 1000 kg which is moving with the acceleration of 1 m/s2 in the upward direction, then the tension developed in the string which is connected to lift is

(a)

9800 N

(b)

10,800 N

(c)

11,000 N

(d)

10,000 N

20. Two masses as shown in the figure are suspended from a massless pulley. The acceleration of the system when masses are left free is

(a)

$\frac { 2g }{ 3 }$

(b)

$\frac { g }{ 3 }$

(c)

$\frac { g }{ 9 }$

(d)

$\frac { g }{ 7 }$

21. A mass M is placed on a very smooth wedge resting on a surface without friction. Once the mass is released, the acceleration to be given to the wedge so that M remains at rest is a where

(a)

a is applied to the left and a = gtan θ

(b)

a is applied to the right and a = gtan θ

(c)

a is applied to the left and a = gsin θ

(d)

a is applied to the left and a = gcos θ

22. A wind-powered generator converts wind U(x) energy into electric energy. Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy. For wind speed v, the electrical power output will be proportional to,

(a)

v

(b)

v2

(c)

v3

(d)

v4

23. From a disc of radius R a mass M, a circular hole of diameter R, whose rim passes through the center is cut. What is the moment of inertia of the remaining part of the disc about a perpendicular axis passing through it

(a)

15MR2/32

(b)

13MR2/32

(c)

llMR2/32

(d)

9MR2/32

24. The work done by the Sun’s gravitational force on the Earth is

(a)

always zero

(b)

always positive

(c)

can be positive or negative

(d)

always negative

25. A certain number of spherical drops of a liquid of radius R coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then

(a)

energy = 4 V T $\left( \frac { 1 }{ r } -\frac { 1 }{ R } \right)$is released

(b)

energy = 3 V T $\left( \frac { 1 }{ r } -\frac { 1 }{ R } \right)$is absorbed

(c)

energy = 3 V T $\left( \frac { 1 }{ r } -\frac { 1 }{ R } \right)$is released

(d)

energy is neither released nor absorbed