Electronics Worksheet: Components and Ohm’s Law Test
Remember (Find the topic, use the formula): Find the topic and the formula: V = I × R, I = V ÷ R, R = V ÷ I, P = V × I, units = W × h ÷ 1000. Change mA to A and kΩ to Ω before using a formula. Check: put your answer back into the formula.
NameDateTime takenScore ___ / 40
- 1.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
- 2.🔺 A 2.4 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
- 3.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
- 4.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
- 5.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
- 6.🌈 A resistor has the colour bands yellow, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
- 7.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
- 8.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) energy used each second (d) the colour of light
- 9.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 watt (d) 1 kilowatt-hour (kWh)
- 10.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 0 % (c) 50 % (d) 25 %
- 11.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it does not light (c) it changes colour (d) it makes a sound
- 12.📏 Which unit measures power? (a) ampere (A) (b) watt (W) (c) volt (V) (d) ohm (Ω)
- 13.🔺 A 2 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
- 14.🌈 A resistor has the colour bands yellow, red, brown. What is its value (in ohms)?
- 15.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 17 Ω resistor? (a) red-violet-black (b) brown-violet-brown (c) violet-brown-black (d) brown-violet-black
- 16.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
- 17.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
- 18.🧩 Which component blows if current is high? (a) resistor (b) fuse (c) thermistor (d) capacitor
- 19.📏 How many watts (W) is 2.2 kW?
- 20.True or false: a buzzer beeps for an alarm. (a) True (b) False
- 21.🔍 Which is the odd one out? (a) leave the TV on standby (b) use old filament bulbs (c) leave fridge door open (d) use LED lamps
- 22.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
- 23.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I × R (d) V = I + R
- 24.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
- 25.Which of these saves electricity? (a) run fans in empty rooms (b) use old filament bulbs (c) leave fridge door open (d) switch off empty rooms
- 26.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
- 27.🧩 Which component has coloured bands? (a) motor (b) potentiometer (c) resistor (d) capacitor
- 28.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V + R (c) I = V ÷ R (d) I = R ÷ V
- 29.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
- 30.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
- 31.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
- 32.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 100 (b) 10 (c) 1024 (d) 1000
- 33.🧾 A family uses 160 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
- 34.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
- 35.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
- 36.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
- 37.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
- 38.🔺 A 45 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
- 39.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
- 40.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) bigger (d) stay the same
Answer key
- the one nearest an end
- 0.2
- 13.2
- True
- anode (+)
- 440
- 0.6
- energy used each second
- 1 kilowatt-hour (kWh)
- 5 %
- it does not light
- watt (W)
- 0.25
- 420
- brown-violet-black
- 50
- 24
- fuse
- 2200
- True
- use LED lamps
- 3
- V = I × R
- 100
- switch off empty rooms
- 270
- resistor
- I = V ÷ R
- 10
- cathode (−)
- 0.4
- 1000
- 1440
- 20
- 10
- 7.5
- 1.5
- 3
- ammeter
- bigger
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