Question

A flashlight bulb is connected to two dry cells with an equivalent voltage of 4.50 V. If the bulb draws a current of 12.0 mA (1000mA = 1A), its resistance is (2 points) a 540. Ohms b 375 Ohms c 266 Ohms d 2.66 Ohms e 145 Ohms

Answer 1

Answer:

b. 375 Ohms

Explanation:

Given the following data;

Voltage = 4.5 V

Current = 12 mA

To find the resistance;

Ohm's law states that at constant temperature, the current flowing in an electrical circuit is directly proportional to the voltage applied across the two points and inversely proportional to the resistance in the electrical circuit.

Mathematically, Ohm's law is given by the formula;

$V = IR$

Where;

• V represents voltage measured in voltage.
• I represents current measured in amperes.
• R represents resistance measured in ohms.

Conversion:

1000 mA = 1 A

12 mA = 12/1000 = 0.012 A

$R = \frac {V}{I}$

Substituting into the formula, we have;

$R = \frac {4.5}{0.012}$  

Resistance, R = 375 ohms