The total electric flux for the following closed surface which is kept inside water

(a)

\(\frac { 80q }{ { \varepsilon }_{ 0 } } \)

(b)

\(\frac { q }{ { 40\varepsilon }_{ 0 } } \)

(c)

\(\frac { q }{ { 80\varepsilon }_{ 0 } } \)

(d)

\(\frac { q }{ { 160\varepsilon }_{ 0 } } \)

The relative permittivity of water is _______.

(a)

ε_r = 70

(b)

ε_r = 75

(c)

ε_r = 80

(d)

ε_r = 85

An isolated metal sphere of radius 'r' is given a charge' q'. The potential energy of the sphere is ____________

(a)

\(\frac { { q }^{ 2 } }{ 4\pi { \varepsilon }_{ 0 }r } \)

(b)

\(\frac { { q }^{ } }{ 4\pi { \varepsilon }_{ 0 }r } \)

(c)

\(\frac { { q }^{ } }{ 8\pi { \varepsilon }_{ 0 }r } \)

(d)

\(\frac { { q }^{ 2 } }{ 8\pi { \varepsilon }_{ 0 }r } \)

The direction of electric field at a point the equatorial line due to an electric dipole is

(a)

along the equatorial line towards the dipole.

(b)

along the equatorial line away from the dipole

(c)

parallel to the axis of the dipole and opposite to the direction of dipole moment

(d)

parallel to the axis of the dipole and in the direction of dipole moment.

When three capacitors are joined in series, the total capacitance is

(a)

Equal to the sum of the capacitance

(b)

Greater than the value of the maximum capacitance

(c)

Less than the value of the mininim capacitance

(d)

none of the above

By using law of conservation of electric charge balance the following equations:
₉₂U²³⁸ ⇾ ₉₀Th²³⁴ +________.

(a)

₂He⁴

(b)

₁H³

(c)

₁H²

(d)

₁H¹

Electric lines of force ________.

(a)

intersect each other

(b)

never intersect

(c)

intersect at infinity

(d)

are always parallel

The torque (\(\tau \)) experienced by an electric dipole placed in a uniform electric field (E) at an angle θ with the field is

(a)

pEcosθ

(b)

pE cosθ

(c)

pE sinθ

(d)

2pE sinθ

A toaster operating at 240 V has a resistance of 120 Ω. The power is ______.

(a)

400 W

(b)

2 W

(c)

480 W

(d)

240 W

The temperature co-efficient of resistance for alloys is _____________.

(a)

low

(b)

very low

(c)

high

(d)

very high

Which of the following is an identical?

(a)

germanium, silicon

(b)

silver, wood

(c)

aluminum, constantan

(d)

bakelite, iron

The conductivity is the reciprocal of ______________.

(a)

resistance

(b)

specific resistance

(c)

conductance

(d)

potential difference

Which of the following is not related to joule's law of heating?

(a)

\(H=VIt\)

(b)

\(H={ I }^{ 2 }Rt\)

(c)

\(H=\cfrac { { V }^{ 2 }t }{ R } \)

(d)

\(H=\cfrac { { I }^{ 2 }R }{ t } \)

For which of the following substances, resistance decreases with temperature?

(a)

copper

(b)

platinum

(c)

mercury

(d)

carbon

Three wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. They are placed in a uniform magnetic field and same electric current is passed through them. Which of the following loop configuration will experience greater torque?

(a)

Circle

(b)

Semi-circle

(c)

Square

(d)

All of them

In which of the following pairs of metals of the thermocouple, the emf is maximum?

(a)

Fe-Cu

(b)

Cu-Zn

(c)

Pt-Ag

(d)

Sb-Bi

The orbital magnetic moment of an electron in the second orbit (n = 2) is _______________.

(a)

18.54 x 10^-24 Am²

(b)

18.54 x 10^-34 Am²

(c)

19.44 x 10^-34 Am²

(d)

19.44 x 10^-24 Am²

In an electrical circuit, R, L, C, and AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and current in the circuit is \(\frac{\pi}{3}\). Instead, if C is removed from the circuit, the phase difference is again \(\frac{\pi}{3}\). The power factor of the circuit is

(a)

1/2

(b)

1/\(\sqrt2\)

(c)

1

(d)

\(\sqrt3\)/2

The self-inductance of a straight conductor is ________________.

(a)

zero

(b)

infinity

(c)

very large

(d)

very small

The generator rule is ____________.

(a)

Fleming's left hand rule

(b)

Fleming's right hand rule

(c)

Maxwell's right hand cork screw rule

(d)

Right hand palm rule

During the propagation of electromagnetic waves in a medium __________________.

(a)

electric energy density is double of the magnetic energy density

(b)

electric energy density is half of the magnetic energy density

(c)

electric energy density is equal to the magnetic energy density

(d)

both electric and magnetic energy densities are zero

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

(a)

Hertz

(b)

Maxwell

(c)

Huygens

(d)

Planck

The wavelength of electromagnetic wave produced by Hertz experiment was _____________.

(a)

6mm

(b)

60m

(c)

6000 mm

(d)

60 cm

Electric filament lamp gives rise to _______________spectrum.

(a)

line 

(b)

band

(c)

continuous

(d)

absorption

________ radiations are used to study atomic structure.

(a)

UV

(b)

IR

(c)

X-rays

(d)

Gamma