Alternating current and direct current

4 marks · Normal

A kettle takes a current of 10 A from a 230 V mains supply.

(a)

Calculate the power of the kettle.

[2 marks]

(b)

The kettle is switched on for 2 minutes. Calculate the total energy transferred in this time.

[2 marks]

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Show answer

(a) 2300 W

(b) 276000 J

Common mistakes: Not converting 2 minutes to 120 s; Incorrect substitution

Show mark scheme and worked solution

Marking points

M1a (a) · 1 mark · Correctly uses formula .

A1a (a) · 1 mark · Correct substitution and answer: 10 \times 230 = 2300 W.

M1b (b) · 1 mark · Converts 2 minutes to 120 s; uses or .

A1b (b) · 1 mark · Evaluates 2300 \times 120 = 276000 J.

Worked solution

(a) Power: W

(b) Time = 2 min = 120 s. J