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#### 12th Standard Physics English Medium Free Online Test Creative 1 Mark questions - Part Three

12th Standard EM

Reg.No. :
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Physics

Time : 00:10:00 Hrs
Total Marks : 10
10 x 1 = 10
1. Eight mercury droplets having a radius of 1 mm and charge of 0.066 pC each merge to form one droplet. Its potential is

(a)

2.4 V

(b)

1.2 V

(c)

3.6 V

(d)

4.8 V

2. The potential due to a single point charge falls as

(a)

$\frac { 1 }{ { r }^{ 2 } }$

(b)

$\frac { 1 }{ { r }^{ 3 } }$

(c)

$\frac { 1 }{ { r }^{ } }$

(d)

-$\frac { 1 }{ { r }^{ } }$

3. The emf of a battery is 3 volts and internal resistance 0.125 $\Omega$ . The difference of potential
at the terminal of battery when connected across an external resistance of 1 $\Omega$ is

(a)

1.67 V

(b)

0.67 V

(c)

2.67 V

(d)

3.67 V

4. If a current I is flowing in a straight wire parallel to X-axis and magnetic field is in y-axis then the wire experiences

(a)

in Z-direction

(b)

in Y- direction

(c)

no force

(d)

in X- diection

5. The Q factor of an a.c. circuit containing a resistance R, inductance L and capacitor C is

(a)

$Q=\frac { 1 }{ \sqrt { LC } }$

(b)

$Q=\frac { 1 }{ R } \sqrt { \frac { C }{ L } }$

(c)

$Q=\frac { 1 }{ R } \sqrt { \frac { L }{ C } }$

(d)

$Q=\frac { 1 }{ \sqrt { LR } }$

6. The existence of E.M. waves was confirmed experimentally by

(a)

Hertz

(b)

Maxwell

(c)

Huygens

(d)

Planck

7. Two plane mirror are at right angles to each other. A man stands between them and combs hair with his right hand. In how many of the images will he be seen using his right hand.

(a)

None

(b)

1

(c)

2

(d)

3

8. A plane mirror is placed at the bottom of the tank containing a liquid of refractive index J.1.P is a small object at a height h above the mirror, an observer O-vertically above P outside the liquid. See p and its image in the mirror. The apparent distance between these two will be

(a)

$2\mu h$

(b)

$\cfrac { 2h }{ \mu }$

(c)

$\cfrac { 2h }{ \mu -1 }$

(d)

$h\left( 1+\cfrac { 1 }{ \mu } \right)$

9. The anode plate in an experiment on photoelectric effect is kept vertically above the emitter plate. Light source is put on. An electric field is switched on which has vertically downward direction.

(a)

The photo current will increase

(b)

The kinetic energy of the electrons will increase

(c)

The stopping potential will decrease

(d)

The transhold wavelength will increase

10. An oil drop carrying a charge q has a mass m kg. It is falling freely in air with terminal speed v. The electric field required to make the drop move upwards with the same speed is

(a)

$\frac{mg}{q}$

(b)

$\frac{2mg}{q}$

(c)

$\frac{mgv}{q^2}$

(d)

$\frac{2mgv}{q}$