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#### 12th Standard Physics English Medium Free Online Test Book Back 1 Mark Questions with Answer Key - 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. Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is

(a)

8.80 × 10-17 J

(b)

-8.80 × 10-17 J

(c)

4.40 × 10-17 J

(d)

5.80 × 10-17 J

2. In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, the resistance of a 60W bulb for use in USA will be

(a)

R

(b)

2R

(c)

$\frac{R}{4}$

(d)

$\frac{R}{2}$

3. A non-conducting charged ring of charge q, mass m and radius r is rotated with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is

(a)

$\\ \frac { q }{ m }$

(b)

$\\ \frac { 2q }{ m }$

(c)

$\\ \frac { q }{ 2m }$

(d)

$\\ \frac { q }{ 4m }$

4. Th e current i fl owing in a coil varies with time as shown in the fi gure. Th e variation of induced emf with time would be

(a)

(b)

(c)

(d)

5. Consider an oscillator which has a charged particle and oscillates about its mean position with a frequency of 300 MHz. Th e wavelength of electromagnetic waves produced by this oscillator is

(a)

1 m

(b)

10 m

(c)

100 m

(d)

1000 m

6. An air bubble in glass slab of refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness of the slab is,

(a)

8 cm

(b)

10 cm

(c)

15 cm

(d)

20 cm

7. A light source of wavelength 520 nm emits 1.04 × 1015 photons per second while the second source of 460 nm produces 1.38 × 1015 photons per second. Then the ratio of power of second source to that of first source is

(a)

1.00

(b)

1.02

(c)

1.5

(d)

0.98

8. In J.J Thomson e/m experiment, a beam of electron is replaced by that of muons (particle with same charge as that of electrons but mass 208 times that of electrons). No deflection condition is achieved only if

(a)

B is increased by 208 times

(b)

B is decreased by 208 times

(c)

B is increased by 14.4 times

(d)

B is decreased by 14.4 times

9. If a half –wave rectifi ed voltage is fed to a load resistor, which part of a cycle the load current will flow?

(a)

00–900

(b)

900–1800

(c)

00–1800

(d)

00–3600

10. The given electrical network is equivalent to

(a)

AND gate

(b)

OR gate

(c)

NOR gate

(d)

NOT gate