Question

Sub:- Physics
1.
In a house, four 60 W electric bulbs are lighted for 2 hours and two 100 W
energy consumed in the house for 30 days.
An electric bulb draws a current of 0.8 A and works on 250 V on the average
monthly bill for 30 days.
wire is cut into three equal parts and then connected in parallel .How will
Which gas is filled in the electric bulb and why?
B
A
20. Why are electric bulbs filled with chemically inactive nitrogen or argon?
Two electric bulbs A and B are marked 220V, 40W and 220V, 60W respectiv
5. (a) Why an ammeter likely to burn out if you connect it in parallel?
(b) Why is series arrangement not found satisfactory for domestic lights?
(a) Define electric power. A device of resistance R is connected across a source
for power in terms of voltage and resistance.​

Answer 1

Answer:

B and argon is gas filled in

Answer 2

• Filling a bulb with an inert gas such as argon or nitrogen slows down the evaporation of the tungsten filament compared to operating it in a vacuum.
• An ammeter is likely to burn if connected in parallel because ammeter is a low resistance device and when connected in parallel, the resistance of the circuit reduces considerably. Hence, a large current flows in the circuit which may lead to burning of a circuit.
• There is voltage division in series circuits. Each component of a series circuit receives a small voltage for a large supply voltage. As a result, the amount of current decreases and the device becomes hot.
• The rate at which energy is transferred by an electrical circuit is known as electric power. It measure in Watts (W).

1 W = 1 J/s

P = I V

From ohm's law,

V = I R

⇒P = I²R = V²/R