Question

The circuit shows a battery and a variable resistor supplying power to a light circuit. As the variable resistor is moved towards left, the bulbs dim a little. What happens if the variable resistor is moved all the way to the right?

• A. The lights brighten considerably
• B. The total circuit resistance increases
• C. The total circuit current decreases
• D. The total applied voltage increases
• E. The total power used in the circuit increases

Answer 1

The correct option is A The lights brighten considerably

When the resistor is moved towards left , total resistance of the circuit increases and hence current in circuit decreases , so bulbs dim a little . The reverse process will happen when the resistor is moved towards right , total resistance decreases and current increases therefore bulbs will light brighten considerably and also the total power used will increase.