Which has a higher resistance, a 40W-220 V bulb, or a 1 kW-220V electric heater ?

08/12/2023 WNA24 77 Views 0 Comments

Which has a higher resistance, a 40W-220 V bulb, or a 1 kW-220V electric heater ?

Ans: – As we know, p = v ^ 2 / R;

So, 40w will have more resistance.

What is the maximum current that a 100W, 220 V lamp can withstand?

Ans: – As we know, I = p/v;

Here, I = ? P= power =100w, v = voltage = 220v,

So, I = 100/220 = 10/22.

How many units of electricity will be consumed by a 60 W lamp in 30 days ifthe bulb is lighted 4 hours daily?

Ans: – Electricity consumed = power × time,

So, Q= 60×30×4= 7.2 KWH.

How many joules of electrical energy will a quarter horse power motor consume in one hour?

Ans: – we know the hors power is 746w,

So, power consume by motor is (746×1/4× 3600) =6714000J.

An electric heater is used on 220 V supply and draws a current of 5 A. What is its electric power?

Ans: – Electric power= V×I,

Or, P= 220×5 = 1100W.

Which uses more energy, a television of 250 W in 60 minutes or a toaster of1.2 kW in (1/6) th of an hour?

Ans: – The energy used by television is more than the toaster.

E(Television)= 250×1/1000 = 0.25KW,

E(toaster)= 1.2×1/6 = 0.2KW.