One Hundred meters of a certain type of wire has a resistance of 7.2 ohms. What is the resistance of 2.5 m of this wire? a. 18 ohm b. 1.8 ohm c. 0.18 ohm d. 3.0 ohm e. 0.30 ohm

The resistance of 2.5 m wire is 0.18 ohm.

Option C.

Explanation:

Resistance is the measure of obstacle given to the flow of currrent. As per ohm's law, resistance is the constant of proportionality between voltage and current. But the resistance of each circuit depends upon the nature of resistor used in that circuit.

R =

So the resistance depends upon the resistivity of the material, length of the material and inversely proportional to the cross sectional area of the material.

In this case, the length of the wire is varied and the composition and cross section is kept constant. From the formula, it can be seen that resistance is directly proportional to the length of the resistor. So if the wire acting as resistor undergoes a decrease in length from 100 m to 2.5 m then there will be decrease in the resistance of the wire also.

Let be the resistance of 100 m wire and be the resistance of 2.5 m wire.

Then, , remaining all parameters will get canceled out due to the usage of same wire with same cross sectional area.

So,

So the resistance of 2.5 m wire is 0.18 ohm.

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.