Physics Answers

Explain how pure metal and a semi conductor can be distinguished through the effect of temperature on their electrical resistance

A car is driving at constant speed down the road.  The mass of the car is 1350 kg and the coefficient of rolling friction is 0.18?  How much engine force is needed to keep the car moving? [Hint:  Draw a free body diagram]

5. a) Define viscosity. 

b) A matter has a body-centered cubic unit cell with a length of 330 𝑝𝑚 along an edge

and a density of 8.57 𝑔 𝑐𝑚−3

. Calculate the atomic mass of the matter.

c) Find the total energy of a moving object of mass 6.3 𝑘𝑔 and momentum

11.5 × 106 𝑘𝑔𝑚𝑠

−1

.

4. a) Define the elastic modulus. Explain the different types of elastic modulus.

b) State and explain Einstein's Photoelectric Effect theory.

c) If 12𝑁 force is applied to a fluid of cross-section 5.34 𝑐𝑚2 with a shearing rate of

0.7 𝑠

−1

then find the viscosity of the fluid.

3. a) Define crystal and unit cell 

b) Explain de Broglie wave and the photoelectric effect. 

c) A wire of length 7 𝑚 and radius 2.37 𝑚𝑚 is stretched by a load of 12370 𝑔𝑚 and

increased by 1.78% of the original length. Find the stress, strain, and Young’s

modulus of the material of the wire.

1. a) Define elasticity of a matter. 

b) Define stress and strain. Explain different types of stress and strain. 

c) The radius of a silver bar is 30 𝑐𝑚. What force is required to stretch the bar by

12.7% of its length where Young’s modulus is 𝑌 = 7.25 × 1010 𝑁𝑚−2

.

a) Define elasticity of a matter. 1 b) Define stress and strain. Explain different types of stress and strain. 1+4 c) The radius of a silver bar is 30 𝑐𝑚. What force is required to stretch the bar by 12.7% of its length where Young’s modulus is 𝑌 = 7.25 × 1010 𝑁𝑚−2 . 

a current of 3A flows past a particular point in a circuit. calculate the charge that passes through if the time that the current flows for is 1 hour

a current of 3A flows past a particular point in a circuit. calculate the charge that passes through if the time that the current flows for is 1 minute

a current of 3A flows past a particular point in a circuit. calculate the charge that passes through if the time that the current flows for is 5s