A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

(a)

Capacitance

(b)

Charge

(c)

Voltage

(d)

Energy density

The value of constant 'K' in coulomb law is _____________.

(a)

0.9 x 10⁹ Nm² C²

(b)

9 x 10^-9 Nm²C²

(c)

9 x 10⁹ Nm^-2 C^-2

(d)

9 x 10⁹ Nm² C^-2

Four plates each of area N and inferplate separation 'd' are placed as shown in figure. The two inner plates are connected to the point 'B' and outer to point 'A'. What is equivalent capacitance?

(a)

\(\frac { { \varepsilon }_{ 0 }A }{ d } \\ \)

(b)

\(\frac { {2 \varepsilon }_{ 0 }A }{ d } \\ \)

(c)

\(\frac { {3 \varepsilon }_{ 0 }A }{ d } \\ \)

(d)

\(\frac { {4 \varepsilon }_{ 0 }A }{ d } \\ \)

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of ______.

(a)

each of them increases

(b)

each of them decreases

(c)

copper increases and germanium decreases

(d)

copper decreases and germanium increases

Which of the following has negative temperature coefficient of resistance?

(a)

copper

(b)

tungsten

(c)

carbon

(d)

silver

A non-conducting charged ring carrying a charge of q, mass m and radius r is rotated about its axis 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)

\(\\ \frac { q }{ 4m } \)

The direction of magnetic field close to a straight conductor carrying current will be _______________.

(a)

along the length of the conductor

(b)

radially outward

(c)

circular in a plane perpendicular to the conductor

(d)

helical

In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 µF, then the voltage across L is

(a)

600 V

(b)

4000 V

(c)

400 V

(d)

1 V

The phase difference between VL and Vc is _________________

(a)

2π

(b)

π/2

(c)

π/4

(d)

π

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is, ______.

(a)

2.5 cm

(b)

5cm

(c)

10 cm

(d)

15cm

Two plane mirrors are parallel to each other and spaced 20cm apart. An object is kept in between them at 15cm from A. out of the following at which point on the image is not formed in mirror A (distance measured from mirror A) ___________.

(a)

15 cm

(b)

25 cm

(c)

45 cm

(d)

55 cm

In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would _____.

(a)

increase by 2 times

(b)

decrease by 2 times

(c)

decrease by 4 times

(d)

increase by 4 times

Light exhibits _______ duality.

(a)

particle-wave

(b)

solid-liquid

(c)

liquid-gas

(d)

gas-plasma

Energy of each photon is ______

(a)

\(\frac{2}{3}\) hv

(b)

3 hv

(c)

2 hv

(d)

hv

Photoelectric cells are of _______ types.

(a)

two

(b)

three

(c)

four

(d)

five

In burglar-alarm, ________ is continuously made to fall' on the photo cell.

(a)

radio waves

(b)

UV rays

(c)

visible light

(d)

\(\gamma\)-rays

Wavelength of X-rays is ______ the wavelength of visible light

(a)

smaller than

(b)

greater than

(c)

negligible when compared to

(d)

equal to

The ratio between the radius of first three orbits of hydrogen atom is _____.

(a)

1:2:3

(b)

2:4:6

(c)

1:4:9

(d)

1:3:5

In a discharge tube, the source of positive rays is ________________.

(a)

cathode

(b)

anode

(c)

gas atoms present in the discharge tube

(d)

fluorescent screen

The ground-state energy of hydrogen atom is ____________ eV

(a)

-13.6

(b)

-18.7

(c)

18.6

(d)

\(\frac{1}{13.6}\)

The specific characteristic of a common emitter amplifier is _______________.

(a)

High input resistance

(b)

Low power gain

(c)

Signal phase reversal

(d)

Low current gain

In a p-n junction diode _________________.

(a)

the current in the reverse biased condition is generally very small

(b)

the current in the reverse biased condition is small but the forward biased current is independent of the biased voltage

(c)

the reverse biased current is strongly dependent on the applied bias voltage.

(d)

the forward biased current is very small in comparison to reverse biased current

In a television, the picture signals are _________ modulated.

(a)

amplitude

(b)

frequency

(c)

phase

(d)

pulse-code

The transmitter in a RADAR is a high power ________.

(a)

cyclotron oscillator

(b)

magnetron oscillator

(c)

Hartley oscillator

(d)

simple harmonic oscillator

__________ Scanning Electron Micrograph (SEM) showing the nano structures on the surface of a leaf from a lotus plant

(a)

Parrot fish

(b)

Morpho butterfly

(c)

Lotus leaf surface

(d)

Peacock feathers