When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as plane sheet of glass. This implies that the liquid must have refractive index, ______.

(a)

less than one

(b)

less than that of glass

(c)

greater than that of glass

(d)

equal to that of glass

When light is incident on a soap film of thickness 5 x 10^–5 cm, the wavelength of light reflected maximum in the visible region is 5320 Å. Refractive index of the film will be, _____.

(a)

1.22

(b)

1.33

(c)

1.51

(d)

1.83

Two plane mirrors are at 45° to each other. If an object is placed between them then the number of images will be ________________.

(a)

5

(b)

9

(c)

7

(d)

8

A ray of light is incident normally on a lane mirror. The angle of reflection will be _____________.

(a)

0°

(b)

90°

(c)

will not be reflected

(d)

None of these

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

All of the following statement are correct except _____________.

(a)

The magnification produced by a convex mirror is always less than one

(b)

A virtual, erect same sized image can be obtained using a plane mirror

(c)

A virtual, erect magnified image can be formed using a concave mirror

(d)

A real, inverted, same-sized image can be formed using a convex mirror

When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is \(\frac{V}{4}\). The threshold wavelength for the metallic surface is _____.

(a)

4λ

(b)

5λ

(c)

\(\frac{5}{2}λ\)

(d)

3λ

A light source of wavelength 520 nm emits 1.04 x 10¹⁵ photons per second while the second source of 460 nm produces 1.38 x 10¹⁵ photons per second. Then the ratio of power of second source to that of first source is _____.

(a)

1.00

(b)

1.02

(c)

1.5

(d)

0.98

As the intensity of incident light increases ______________.

(a)

K.E of emitted photo electrons increases

(b)

photoelectric current decreases

(c)

photoelectric current increases

(d)

K.E of emitted photo electrons decreases

According to special theory of relativity the only constant in all frames is _____________.

(a)

mass

(b)

length

(c)

time

(d)

velocity of light

The light photon has _______ nature.

(a)

wave

(b)

particle

(c)

matter

(d)

dual

Total angular momentum of a moving electron is an integral multiple of _______

(a)

h

(b)

λ

(c)

\(\frac { h }{ 2\pi } \)

(d)

2π

The ratio of the wavelengths radiation emitted for the transition from n = 2 to n = 1 in Li⁺⁺, He⁺ and H is _____.

(a)

1:2:3

(b)

1:4:9

(c)

3:2:1

(d)

4:9:36

Wave number is defined as the number of wave ____________.

(a)

produced in one second

(b)

in a distance of 1 metre

(c)

in a distance of 3 x 10⁸ m

(d)

in a distance of λ metre

Arrange the spectral lines H_α, H_β, H_γ, H_δ in the increasing order of their wavelength.

(a)

H_α, H_β, H_⋎, H_δ

(b)

H_δ, H_⋎, H_β, H_α

(c)

H_β, H_α H_δ, H_⋎

(d)

H_α, H_β, H_γ, H_δ

Bohr's radius gives the radius of the _________ orbit.

(a)

first

(b)

second

(c)

third

(d)

fourth

A forward biased diode is treated as ________________.

(a)

An open switch with infinite resistance

(b)

A closed switch with a voltage drop of 0V

(c)

A closed switch in series with a battery voltage of 0.7V

(d)

A closed switch in series with a small resistance and a battery

To obtain sustained oscillation in an oscillator,______.

(a)

Feedback should be positive

(b)

Feedback factor must be unity

(c)

Phase shift must be 0 or 2π

(d)

All the above

The output current versus time curve of a rectifier is shown in the figure. The average value of the output current is ______________.

(a)

0

(b)

\(\frac{I_0}{2}\)

(c)

\(\frac { 2{ I }_{ 0 } }{ \pi } \)

(d)

I_o

To obtain OR gate from NOR gate, you will need __________

(a)

one NOR gate

(b)

one NOT gate

(c)

two NOT gate

(d)

one OR gate

Energy gap between valence band and conduction band is called as the _____________

(a)

forbidden energy gap

(b)

conduction band gap

(c)

valence band gap

(d)

filled band gap

The internationally accepted frequency deviation for the purpose of FM broadcasts ____________.

(a)

75 kHz

(b)

68 kHz

(c)

80 kHz

(d)

70 kHz

The made of propagation used by short wave broadcast services is _______________.

(a)

space wave

(b)

skywave

(c)

ground wave

(d)

both (a) & (c)

The materials used in Robotics are _____.

(a)

Aluminium and silver

(b)

Silver and gold

(c)

Copper and gold

(d)

Steel and aluminum

Muscle wires can contract by _________ when electric current is passed through them.

(a)

5%

(b)

7%

(c)

25%

(d)

50%