Question

The differences between microwaves and infrared radiation are due to differences in their _____.


A 25 V battery is connected into a circuit with two resistors in series. One resistor has resistance 5.0 Ω and the other has resistance 7.5 Ω. What is the voltage drop across the 7.5 Ω resistor?

Answer 1

Answer:

15 V

Explanation:

From the question,

For series connection: (i) Both resistor have a common current flowing through the (ii) The combined resistance = R1+R2

Rt = R1+R2.................. Equation 1

Given: R1 = 5 ohms, R2 = 7.5 ohms.

Rt = 5+7.5 = 12.5 ohms.

Applying Ohm's law,

V = IRt................... Equation 2

Where V = Voltage, I = current.

make I The subject of the equation

I = V/Rt.............. Equation 3

Given: V = 25 V, Rt = 12.5 ohms.

Substitute into equation 3

I = 25/12.5

I = 2 A.

Now,

Voltage drop across the 7.5 ohms resistor = R2×I

Voltage drop across the 7.5 ohms resistor = 7.5×2

Voltage drop across the 7.5 ohms resistor = 15 V