Electrical Principles Quiz

The current flowing through a resistor is 0.8 A when a p.d. of 20 V is applied. Determine the value of the resistance. From ohms law, Resistance 𝑅 = 𝑉 𝐼 = 20 0.8 = 25Ω

Determine the p.d. which must be applied to a 2 KΩ resistor in order that a current of 10 mA may flow. Resistance 𝑅 = 2𝐾Ω = 2 × 103 = 2000Ω Current 𝐼 = 10 𝑚𝐴 = 10 × 10−3𝐴

A 100 V battery is connected across resistor and causes a current of 5 mA to flow. Determine the resistance of the resistor. If the voltage is now reduced to 25 V, what will be the new value of the current flowing? Resistance 𝑅 = 𝑉 𝐼 = 100 5×10−3 =20 × 103 = 20𝐾Ω

A 100 W electric light bulb is connected to a 250 V supply. Determine a) the current flowing in the bulb, and b) the resistance of the bulb. Power 𝑃 = 𝑉 × 𝐼, from which, current 𝐼 = 𝑃𝑉 a) Current 𝐼 = 100 250 = 0.4 𝐴 b) Resistance 𝑅= 𝑉 𝐼 = 250 0.4 = 625Ω

Tags

NGSS.HS-PS3-1

Calculate the power dissipated when a current of 4 mA flows through a resistance of 5kΩ. Power P= 𝐼 2𝑅 = 4× 10−3 × 5 × 103=80× 10−3 = 0.80𝑊 𝑜𝑟 80𝑚𝑊

What does 'SI units' mean?

Which electrical instrument would you use to measure current in an electric circuit?

• Ammeter

• Clamp metre

A charge of 240 Coulombs is transferred in 2 minutes in an electric circuit, what is the amount of current flowing through it?

What is Ohms law?

What is the power dissipated by a resistor of 10 Ω when a current of 2 A passes through it?