Resistance and resistivity are related by a: A: factor that is dependent on the length of the material
B: proportionality constant dependent on the source of the material
C: factor that is dependent on the area of the material
D: proportionality constant dependent on the identity of the material

D

Explanation: Resistance of current in a wire is directly proportional to the length of the wire and inversely proportional to the cross - sectional area of the wire. That is,

R = (rho × L)/A

Where

L = length of the wire

A = cross sectional Area of the wire

rho = resistivity = proportionality constant which depends on the quality of the wire.

Therefore, Resistance and resistivity are related by a:

proportionality constant dependent on the identity of the material.

b.

explanation:

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards