Question

A 100 Ω electric iron is connected to 200 V, 50 Hz ac source. Calculate average power delivered to iron, peak power and energy spent in one minute?

Options

• 400 W, 800 W, 12 × 10⁵ J

• 400 W, 900 W, 1.2 × 10⁵ J

• 500 W, 800 W, 6 × 10⁵ J

• 400 W, 900 W, 60 × 10⁵ J

Answer 1

400 W, 800 W, 12 × 10⁵ J

Explanation:

Here, R = 100 Ω, E_v = 200 V, n = 50 Hz

Average power/cycle = `"E"_"v""I"_"v" = "E"_"v" xx "E"_"v"/"R"`

`= (200)^2/100` = 400 watt

Peak power/cycle = `"E"_0"I"_0 = sqrt 2 "E"_"v" xx sqrt 2 "I"_"v"`

= 2 E_vI_v = 2 × 400 = 800 W

As the frequency is 50 Hz

∴ Average power spent in one second = 400 × 50

∴  Energy spent in one minute = 400 × 50 × 60 = 12 × 10⁵ J