Which changes would cause an increase in the resistance of a wire? Check all letters that apply.

a) increasing its temperature

b) decreasing its temperature

c) using a longer wire

d) using a shorter wire

e) using a thicker wire

using a thinner wire

Answer

a) increasing its temperature

c) using a longer wire

g) using a thinner wire

Explanation

a) increasing its temperature

Increasing the temperature of a conductor increases the kinetic energy of the free electrons making them to collide as they travel. This prevents the free movement of electrons that act as charge carriers.

c) using a longer wire

The longer the wire the more resistance it has. Resitance of a wire is directly proportional to its length.

g) using a thinner wire

A thinner wire has few electrons hence more resistance.

The correct answers are:

A) increasing its temperature

C) using a longer wire

G) using a thinner wire

A) When we increase the temperature of the wire, the atoms of the wire move more and faster, so if a current passes through the wire, the electrons of the current collide more with the atoms of the wire: thus, the resistance increases.

C) When we use a longer wire, the current must flow through a longer path, thus the electrons of the current collide more with the atoms of the wire, and the resistance increases.

G) When we use a thinner wire, we increase the cross-sectional density of atoms in the wire, thus the electrons in the current collide more with the atoms of the wire, and the resistance increases.