Resistors and Ohm's Law Video Lessons

Concept

# Problem: 1. The current through a 10-ohm resistor connected to a 120-V power supply isa) 1 Ab) 10 Ac) 12 Ad) 120 Ae) none of these2. A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?a) 5 Vb) 10 Vc) 15 Vd) 20 Ve) more than 20 V3. The electric power of a lamp that carries 2 A at 120 V isa) 1/6 wattsb) 2 wattsc) 60 wattsd) 20 wattse) 240 watts4. On some early automobiles, both headlights went out when one bulb burned out. The headlights must have been connected ina) parallelb) perpendicularc) seriesd) haste5. When a 60-watt light bulb is connected to a 120-volt source the current in the light bulb isa) 0.25 A.b) 0.5 A.c) 2 A.d) 4 A.e) more than 4 A.

###### FREE Expert Solution

In this problem, we're mainly going to use Ohm's law.

Ohm's law:

$\overline{){\mathbit{i}}{\mathbf{=}}\frac{\mathbf{V}}{\mathbf{R}}}$, where is current, V is voltage, and R is resistance.

1.

i = V/R = 120/10 = 12 A

The correct option is c) 12 A.

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###### Problem Details

1. The current through a 10-ohm resistor connected to a 120-V power supply is
a) 1 A
b) 10 A
c) 12 A
d) 120 A
e) none of these

2. A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?
a) 5 V
b) 10 V
c) 15 V
d) 20 V
e) more than 20 V

3. The electric power of a lamp that carries 2 A at 120 V is
a) 1/6 watts
b) 2 watts
c) 60 watts
d) 20 watts
e) 240 watts

4. On some early automobiles, both headlights went out when one bulb burned out. The headlights must have been connected in
a) parallel
b) perpendicular
c) series
d) haste

5. When a 60-watt light bulb is connected to a 120-volt source the current in the light bulb is
a) 0.25 A.
b) 0.5 A.
c) 2 A.
d) 4 A.
e) more than 4 A.