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 = \(\frac{-dx}{dV}\)

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

Which one of the following represents current magnetic field lines?

(a)

(b)

(c)

(d)

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

Electromagnetic waves are discovered by _______________.

(a)

Hertz

(b)

Maxwell

(c)

Lenz

(d)

Huygens

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

(a)

2 mm, 8 mm, 18 mm

(b)

2 mm, 18 mm, 28 mm

(c)

2 mm, 18 mm, 22 mm

(d)

2 mm, 18 mm, 58 mm

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)

white radiations

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 V_B is generated

(d)

Energy V_B is to be surrounted before any charge can flow across junction

How will you increase the resistivity of Ge semi conductor?

(a)

on adding donar impurity

(b)

on adding acceptor impurity

(c)

on making UV light incident on Ge crystal

(d)

on decreasing the temperature

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

(a)

ground waves

(b)

surface waves

(c)

space waves

(d)

skywaves