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#### 12th Standard Physics English Medium Free Online Test Creative One 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. Electric field intensity and electric potential are related by_________.

(a)

E=-$\frac{dV}{dt}$

(b)

E=-$\frac{dV}{dx}$

(c)

E=$\frac{dV}{dt}$

(d)

E=$\frac{-dx}{dV}$

2. When a current of 5 A flows through a conductor of resistance 3 $\Omega$ the loss of power due to joule heating effect is_________

(a)

75 W

(b)

25 W

(c)

70.7 W

(d)

45 W

3. Which one of the following represents corrent magnetic field lines?

(a)

(b)

(c)

(d)

4. If a secondary coil has 40 turns, and a primary coil with 20 turns is charged with 50V of potential difference, then potential difference in secondary would be

(a)

50 V

(b)

25 V

(c)

60 V

(d)

100 V

5. Electromagnetic waves are discovered by

(a)

Hertz

(b)

Maxwell

(c)

Lenz

(d)

Huygens

6. A point object 0 is placed between two plane mirrors as shown is figure The distance by mirror M2 from it are

(a)

2 mm, 8 mrn, 18 mm

(b)

2 mm, 18 mm, 28 mm

(c)

2 mm, 18 mm, 22 mm

(d)

2 mm, 18 mrn, 58 mm

7. The fig. represents the observed intensity of X-rays emitted by an X-ray tube as a function of wavelength. The sharp peaks A and B denote

(a)

continuous spectrum

(b)

band spectrum

(c)

characteristic spectrum

(d)

8. 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

9. How will you increase the resistivity of Ge semi conductor?

(a)

(b)

(c)

on making UV light incident on Ge crystal

(d)

on decreasing the temperature

10. The waves that are bent down by the ionosphere on are

(a)

ground waves

(b)

surface waves

(c)

space waves

(d)

skywaves