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

12th Standard EM

Reg.No. :
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Physics

Time : 00:10:00 Hrs
Total Marks : 10
10 x 1 = 10
1. In a hydrogen atom the electron revolves around the proton in an orbit of 0.53 $\mathring { A }$. The potential produced by the electron on the nuleus is

(a)

6.8 V

(b)

13.6 V

(c)

54.4 V

(d)

27.2 V

2. If the specific resistance of a potentiometer wire is 10-7 Om and current flowing through it . is 0.1 amp, cross - sectional area of wire is 10-6 m2, then potential gradient will be

(a)

10-2 v/m

(b)

10-4 v/m

(c)

10-6 v/m

(d)

10-8v/m

3. The reciprocal of conductivity is________

(a)

specific conductance

(b)

specific resistance

(c)

resistance

(d)

conductance

4. Direction of magnetic force on a positive charge moving in a magnetic field is given by

(a)

thumb rule

(b)

left hand rule

(c)

right hand rule

(d)

cork screw rule

5. Electric filament lamp gives rise to

(a)

line spectrum

(b)

continuous spectrum

(c)

continuous absorption spectrum

(d)

line absorption spectrum

6. A point object is placed at a distance of 30 cm from a convex mirror of focal length 30 cm, The image will from at

(a)

Infinity behind the mirror

(b)

Focus

(c)

Pole

(d)

15 cm

7. The phenomena by which metals emit electrons under the influence of radiation is called ________

(a)

interference

(b)

polarization

(c)

ionization

(d)

photoelectric effect

8. If R is Rydberg's constant, the muumum wavelength of hydrogen spectrum is

(a)

1/R

(b)

R/4

(c)

4/R

(d)

R

9. Natural uranium consists of _____________ % of U235 and __________% of U238

(a)

0.72, 99.28

(b)

99.28, 0.72

(c)

77.28, 72

(d)

72, 77.28

10. Which statement is incorrect regarding for p-n junction.

(a)

Donor atoms are depleted of their holes in junction

(b)

No net charge exists far from junction

(c)

Barrier potential VB is generated

(d)

Energy VB is to be surmounted before any charge can flow across junction