When a test charge is brought near a charged object, we know from coulomb's law that it will experience a net force (either attractive or repulsive, depending on the nature of the object's charge). a test charge may also experience an electric force when brought near a neutral object. any attraction of a neutral insulator or neutral conductor to a test charge must occur through induced polarization. in an insulator, the electrons are bound to their molecules. though they cannot move freely throughout the insulator, they can shift slightly, creating a rather weak net attraction to a test charge that is brought close to the insulator's surface. in a conductor, free electrons will accumulate on the surface of the conductor nearest the positive test charge. this will create a strong attractive force if the test charge is placed very close to the conductor's surface.
1. what is the nature of the force between balls a and b?
a) strongly attractive.
b) strongly repulsive.
c) weakly attractive.
d) neither attractive nor repulsive.
2. what is the nature of the force between balls a and c?
a) strongly attractive.
b) strongly repulsive.
c) weakly attractive.
d) neither attractive nor repulsive .

1. (a)strongly attractive

2 (c) weakly attractive.

Explanation:

Consider three plastic balls (A, B, and C), each carrying a uniformly distributed charge equal to either +Q, -Q or zero, and an uncharged copper ball (D). A positive test charge (T) experiences the forces shown in the figure when brought very near to the individual balls. The test charge T is strongly attracted to A, strongly repelled from B, weakly attracted to C, and strongly attracted to D.

should be the concluding part to this question as presented above

1. What is the nature of the force between balls A and B?

a) strongly attractive.

b) strongly repulsive.

c) weakly attractive.

d) neither attractive nor repulsive.

since there is an attractive force between ball A and the test charge, the charge on ball A must be negative

A = -Q

since ball B is repulsive to the test charged , then B must be positively charged

B = +Q

since A is negative and B is positive , then they will experienced a  strong attraction

option A

2. What is the nature of the force between balls A and C?

a) strongly attractive.

b) strongly repulsive.

c) weakly attractive.

d) neither attractive nor repulsive .

Since C is weakly attracted to the test charge, we can say that Ball C will be weakly attracted to A, because it possess some weka charges

option C

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.