#### 11th Standard Physics Properties of Matter English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

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Physics

Time : 00:20:00 Hrs
Total Marks : 20

Answer all the questions

20 x 1 = 20
1. If a wire is stretched to double of its original length, then the strain in the wire is

(a)

1

(b)

2

(c)

3

(d)

4

2. For a given material, the rigidity modulus is $\left( \frac { 1 }{ 3 } \right)$rd of Young’s modulus. Its Poisson’s ratio is

(a)

0

(b)

0.25

(c)

0.3

(d)

0.5

3. Two wires are made of the same material and have the same volume. Th e area of cross sections of the fi rst and the second wires are A and 2A respectively. If the length of the fi rst wire is increased by Δl on applying a force F, how much force is needed to stretch the second wire by the same amount?

(a)

2

(b)

4

(c)

8

(d)

16

4. Th e Young’s modulus for a perfect rigid body is

(a)

0

(b)

1

(c)

0.5

(d)

infinity

5. If the temperature of the wire is increased, then the Young’s modulus will

(a)

remain the same

(b)

decrease

(c)

increase rapidly

(d)

increase by very a small amount

6. 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

7. The wettability of a surface by a liquid depends primarily on

(a)

viscosity

(b)

surface tension

(c)

density

(d)

angle of contact between the surface and the liquid

8. An air bubble of diameter 4 mm rises steadily i through a solution of density 1500 kgm23 at the rate of 30cm-1 the coefficient of viscosity of the solution is

(a)

3.3 x 10-3 poise

(b)

2.2 x 10-3 poise

(c)

3.3 x 10-3 poise

(d)

4.4 x 10-3 poise

9. Water rises in a capillary tube to a certain height such that the upward force due to the surface tension is balanced by 62.84 x 10-5N force due to the weight of the liquid column. If the surface tension of water is 70 x 10-3Nm the radius of the capillary tube is

(a)

1.43 x 10-3m

(b)

2.83x 10-3 m

(c)

1.43x 10-2 m

(d)

2.83 x 10-3 m

10. Ablack body is continuously radiating ene.rlD' at a temperature of 2880 k if U1 U2 and U3 are the amount of radiation measured between the wavelengths 599 & 600 nm, 999 & 1000 nm & 1499& 1500nin respectively then (wiresconstant b = 2.88 x 1026 kmk)

(a)

U2 < U3

(b)

U1=U2=U3

(c)

U123

(d)

U2>U1>U3

11. If there were no gravity, which oftbe following will not be there for a fluid?

(a)

viscosity

(b)

surface tension

(c)

pressure

(d)

archimedes upward thrust

12. Critical velocity of the liquid

(a)

decreases when radius decreases

(b)

increases when radius increases

(c)

decreases when density increases

(d)

increase when density increases

13. A rectangular vessel when full of water, takes 10 min to be emptied through an orifice in its bottom, how much time will it take to be emptied when half filled with water

(a)

9 min

(b)

7 min

(c)

5 min

(d)

3 min

14. Two drops of equal radius coalesce to form a bigger drop. What is ratio of surface energy of bigger drop to smaller one?

(a)

21/2:1

(b)

1:1

(c)

22/3:1

(d)

none of these

15. Two capillaries of lengths L & 2L and of radii R & 2R are connected in series the net rate of flow of fluid through them will (rate of the flow through singe capillary,$x=\pi R^{4}/8 \eta L$)be

(a)

$\frac{8}{9}\alpha$

(b)

$\frac{9}{8}\alpha$

(c)

$\frac{5}{7}\alpha$

(d)

$\frac{7}{5}\alpha$

16. The water from a tap of diameter 1.25cm with a rate of 5 x 10-5 m3 s-1 the density & coefficient of viscosity of water are 103 kg m-3 & 10-3 pascal the flow of water is

(a)

steady with Reynold's number 5100

(b)

turbulent with Reynold's number 5100

(c)

steady with Reynold's number 3900

(d)

turbulent with Reynold's number 3900

17. The CGS unit of stress is,

(a)

N/m2

(b)

J/m2

(c)

dynl/cm2

(d)

N/cm2

18. Amount of energy required to change liquid to gas and vice versa without any change in temperature is termed as

(a)

Latent Heat and Fusion

(b)

Latent Heat of Yaporis ation

(c)

Heat capacity

(d)

Specific heat capacity

19. Energy due to which molecules held at a fixed position vibrate, this energy is termed as,

(a)

external energy

(b)

internal energy

(c)

chemical energy

(d)

physical energy

20. The viscous force the relative motion between the adjacent layers of a fluid in motion which one of the following is absolutely fit?

(a)

opposes

(b)

never affects

(c)

facilitates

(d)

may effect under certain conditions