A satellite is positioned at a certain altitude above the Earth's surface. Which of the following statements correctly describes the variation of gravitational potential with altitude?

A. Gravitational potential decreases linearly with increasing altitude.

B. Gravitational potential increases exponentially with increasing altitude.

C. Gravitational potential remains constant regardless of altitude.

D. Gravitational potential increases linearly with increasing altitude.

Which of the following best describes a similarity between gravitational fields and electric fields?

A. Both fields are always attractive in nature.

B. Both fields decrease in strength with the square of the distance from the source.

C. Both fields can only exist in a vacuum.

D. Both fields are quantised.

What is the electric potential at a point in space where the electric field is zero?

A. Zero

B. Infinity

C. Constant but not zero

D. Cannot be determined

Two charged particles are placed close to each other. Which of the following statements correctly describes the resultant electric field due to the superposition of their individual fields?

A. The resultant field is always zero.

B. The resultant field is the vector sum of their individual fields.

C. The resultant field is the scalar sum of their individual fields.

D. The resultant field is always in the direction of the stronger charge.

Which of the following is a primary application of Faraday cages?

A. Amplifying electric signals

B. Blocking radio waves

C. Generating electric fields

D. Measuring charge on a body

a) Define 'gravitational potential' at a point in space and explain how it varies with altitude. [3]

b) A satellite is at a height of 2000 km above the Earth's surface. Calculate the change in gravitational potential as it moves to a height of 2500 km. [4]

a) Describe the similarities and differences between gravitational fields and electric fields. [3]

b) If a positive charge is placed in an electric field, in which direction will it move? [2]

a) Define 'equipotential surface' in the context of electric fields. [3]

b) If work is done to move a charge along an equipotential surface, how does the electric potential energy of the charge change? [2]

a) Describe the principle of superposition as it applies to electric fields. [3]

b) Two point charges, Q1 = +3μC and Q2 = -5μC, are separated by a distance of 10 cm. Calculate the resultant electric field at a point midway between the charges. [4]

c) How would the electric field change if Q2 was changed to +5μC? [3]

a) What is meant by 'shielding' in the context of electric fields? [2]

b) Describe the principle behind the operation of a Faraday cage. [3]

c) How does the thickness of the walls of a Faraday cage affect its shielding effectiveness? [3]