# NUST NET SAMPLE PHYSICS QUESTIONS

TOPIC:

Vectors and Equilibrium

QUESTION:

If the magnitude of dot product and cross product of two vectors is 6√3 (6 under root 3) and 6 respectively. The angle between the vectors is?

OPTIONS:

1. 75o
2. 60o
3. 45o
4. 30o

30o

EXPLANATION:

A * B = AB sin ɵ = 6 ….. (i)

A.B = AB cos ɵ = 6√3 …(ii)

Dividing (i) by (ii) : AB sin ɵ / cos ɵ = 6 / 6√3

Tan ɵ = 1 / √3 or ɵ = 30o

TOPIC

Optics

QUESTION

A parallel beam of white light is incident normally on a different grating. It is noted that the second order and third order spectra partially overlap. Which wavelength in third order spectrum appears at the same angle as the wavelength of 600 nm in the second order spectrum?

OPTIONS

1. 300nm
2. 600nm
3. 400nm
4. 900nm

CORRECT OPTION

400nm

EXPLANATION

Note that nλ should be constant.

2 * 600 = 1200

Now 3 * x = 1200, solving gives x = 400nm

TOPIC:

NUCLEAR PHYSICS

QUESTION

Which of the following basic forces is short range?

1. Weak nuclear forces
2. Strong nuclear forces
• Gravitational force

OPTIONS

1. i only
2. iii only
3. i and ii only
4. ii and iii only