# Lesson Worksheet: Ohm’s Law Physics • 9th Grade

In this worksheet, we will practice using the formula V = IR (Ohm’s law) to work out the values of the potential difference, current, and resistance in simple circuits.

Q1:

A resistor in a circuit has a potential difference of 20 V across it. The current through the resistor is 0.4 mA. What is the resistance of the resistor?

Q2:

Which of the following is the correct unit for potential difference?

• AOhm
• BAmpere
• CJoule
• DWatt
• EVolt

Q3:

How many volts are there in 20 kilovolts?

Q4:

A resistor in a circuit has a potential difference of 10 V across it. The current through the resistor is 10 A. What is the resistance of the resistor?

Q5:

What kind of circuit component has a lower resistance if the temperature around the component is higher?

• AAn ohmic conductor
• BAn LED
• CA fuse
• DA diode
• EA thermistor

Q6:

How many millivolts are there in 0.5 volts?

Q7:

Benjamin wants to find out the resistance of a resistor. He connects the resistor to a variable potential difference power source and uses an ammeter to find the current through the resistor. His results are shown in the table. What is the resistance of the resistor?

 Potential Difference (V) Current (mA) 3 6 9 12 15 50 100 150 200 250

Q8:

A student has a resistor of unknown resistance. She places the resistor in series with a source of variable potential difference. Using an ammeter, she measures the current through the resistor at different potential differences and plots her results on the graph as shown in the diagram. What is the resistance of the resistor? Q9:

Ammeters should always be connected in . Voltmeters should always be connected in .

• Aseries, series or parallel
• Bparallel, parallel
• Cseries, series
• Dseries, parallel
• Eparallel, series

Q10:

What kind of circuit component has a lower resistance if the light incident upon it is at a higher intensity?

• AAn LED
• BA thermistor
• CA fuse
• DAn LDR
• EA diode