Physics II Quiz 03 MULTIPLE CHOICE 1 If a quantity you calcu

Physics II Quiz 03 MULTIPLE CHOICE 1) If a quantity you calculated has units of what is that quantity? s2.c A) resistivity B) potential E) charge C) capacitance D) resistance 2) A wire of resistivity e must be replaced in a circuit by a wire of the same material but four times as long. If, however, the total resistance is to remain as before, the diameter of the new wire must A) be the same as the original diameter. B) be one-half the original diameter. C) be four times the original diameter. D) be one-fourth the original diameter E) be two times the original diameter. 3) If we double the resistance in a circuit but keep the current in it constant, the power dissipated by that circuit will B) be one-fourth as great. A) be four times as great. D) be one-half as great C) be two times as great. 4) A current of 5.0 A flows through an electrical device for 10 seconds. How many electrons flow through this -19 B) 31 x 1020 D) 3.1 x 1020 E) 20 A) 2.0 C) 0.20

Solution

Here ,

1)

for the unit

kg.m^2/(s^2.C) = J/C = VOlt

As the volt is unit of potential

B) Potential

2)

as the resistance is diven as

R = Q * L/Area

for 4 times the length, the area must be 1/4 times to have same resistance

hence , the diameter must be 1/2 time

B) be one half the original diameter

3)

as Power = I^2 * R

hence , the power will be two times as great

option C)

4)

number of electrons = 5*10/(1.602 *10^-19)

number of electrons = 3.1 *10^20

option D) 3.1 *10^20