13. A metallic coil connected to a 220V supply has a resistance of 110ohm . how long will it take this coil to heat 1Kg water 200 degree C to 700 degree C ? assume whole heat produced by coil is taken up by water . (specific heat capacity of water = 4186).
6. "The resistance of a conductor is 1ohm."what is meant by this statement.
14.Why is much less heat generated in long electric than filaments of electric bulbs?
15.How does the resistance of wir change when :-
1) Its length is doubled
2)area is doubled.
13. A metallic coil connected to a 220V supply has a resistance of 110ohm . how long will it take this coil to heat 1Kg water 200 degree C to 700 degree C ? assume whole heat produced by coil is taken up by water . (specific heat capacity of water = 4186).
6. "The resistance of a conductor is 1ohm."what is meant by this statement.
14.Why is much less heat generated in long electric than filaments of electric bulbs?
15.How does the resistance of wir change when :-
1) Its length is doubled
2)area is doubled.
1. Here,
V = 220 Volts
R = 110 Ω
s = 4186 Jkg-1K-1
P = V2/R
= 2202/(110)
= 440 W
ΔT = 700 – 200 = 5000C
m = 1 kg
Heat required
H = ms ΔT
H = 1×4186×500
H = P×t
=> P×t = 4186×500
=> t = 4186×500/440
=> t = 4756.8 s
Or time reqd 1 hr 19 min
2.
Resistance of a conductor 1 Ω means the conductor provides resistance to the current such that if the potential difference across the conductor is 1 V, it allows a current of 1A through it.
3.
Heat generated is very less in a filament of a bulb because the filament takes low power. A bulb filament has a high resistance and as because higher is the resistance lesser will be the power, so it gives out less heat per second.
4.
1. If length of a conductor is doubled the resistance is also doubled.
2. If the cross section area is double the resistance becomes half that of the previous.
1. Here,
V = 220 Volts
R = 110 Ω
s = 4186 Jkg-1K-1
P = V2/R
= 2202/(110)
= 440 W
ΔT = 700 – 200 = 5000C
m = 1 kg
Heat required
H = ms ΔT
H = 1×4186×500
H = P×t
=> P×t = 4186×500
=> t = 4186×500/440
=> t = 4756.8 s
Or time reqd 1 hr 19 min
2.
Resistance of a conductor 1 Ω means the conductor provides resistance to the current such that if the potential difference across the conductor is 1 V, it allows a current of 1A through it.
3.
Heat generated is very less in a filament of a bulb because the filament takes low power. A bulb filament has a high resistance and as because higher is the resistance lesser will be the power, so it gives out less heat per second.
4.
1. If length of a conductor is doubled the resistance is also doubled.
2. If the cross section area is double the resistance becomes half that of the previous.
