Question

Physics Drill: Voltage Solve the problems about Voltage below. Show your

complete solutions.

1. It takes 20 J of work to push 4C of charge across the filament of a bulb. Find

the potential difference across the filament.2. The potential difference between two terminals of a cell is 3V. Find the Work

done in moving 5C of charge across the cell.

3. A group of electrons of net magnitude of charge, 𝑄 = 0.50 𝐶, passes through a

cell of voltage, 𝑉𝑐𝑒𝑙𝑙 = 20𝑉, from the (+) to the (-) terminal. What is the change

in energy, ∆𝐸, of the group of electrons as they move across the terminals?

Answer 1

(1) potential

$V=\frac{W}{q}$

$V=\frac{20}{4}=5V$

(2)

Work

$W=qV$

$W=5\times3=15J$

(3)

Change energy

$∆E=q∆V$

$W=0.50\times20=10J$