357133 A filament bulb (500 \(W\), 100 \(V\)) is to be used in a 230 \(V\) main supply. When a resistance \(R\) is connected in series, it works perfectly and the bulb consumes 500 \(W\). The value of \(R\) is

357134 Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating element should be _____ to _____ times of its initial length if the water is to be boiled in 15 minutes.

357135 Assertion :
When current through a bulb decrease by \(0.5 \%\), the glow of bulb decreases by \(1 \%\).
Reason :
Glow which is directly proportional to square of current.

357136 A wire of length 1.0 \(m\) and radius \({10^{ - 3}}m\) is carrying a heavy current and is assumed to radiate as a block body. At equilibrium its temperature is 900\(K\) while that of the surroundings is 300\(K\). The resistance at 900 \(K\) is \(5.68\pi \times {10^{ - 2}}\Omega \). Find the current in the wire. Stefan’s constant \( = 5.68 \times {10^{ - 8}}W{m^{ - 2}}{K^{ - 4}}\).

357133 A filament bulb (500 \(W\), 100 \(V\)) is to be used in a 230 \(V\) main supply. When a resistance \(R\) is connected in series, it works perfectly and the bulb consumes 500 \(W\). The value of \(R\) is

357134 Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating element should be _____ to _____ times of its initial length if the water is to be boiled in 15 minutes.

357135 Assertion :
When current through a bulb decrease by \(0.5 \%\), the glow of bulb decreases by \(1 \%\).
Reason :
Glow which is directly proportional to square of current.

357136 A wire of length 1.0 \(m\) and radius \({10^{ - 3}}m\) is carrying a heavy current and is assumed to radiate as a block body. At equilibrium its temperature is 900\(K\) while that of the surroundings is 300\(K\). The resistance at 900 \(K\) is \(5.68\pi \times {10^{ - 2}}\Omega \). Find the current in the wire. Stefan’s constant \( = 5.68 \times {10^{ - 8}}W{m^{ - 2}}{K^{ - 4}}\).

357133 A filament bulb (500 \(W\), 100 \(V\)) is to be used in a 230 \(V\) main supply. When a resistance \(R\) is connected in series, it works perfectly and the bulb consumes 500 \(W\). The value of \(R\) is

357134 Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating element should be _____ to _____ times of its initial length if the water is to be boiled in 15 minutes.

357135 Assertion :
When current through a bulb decrease by \(0.5 \%\), the glow of bulb decreases by \(1 \%\).
Reason :
Glow which is directly proportional to square of current.

357136 A wire of length 1.0 \(m\) and radius \({10^{ - 3}}m\) is carrying a heavy current and is assumed to radiate as a block body. At equilibrium its temperature is 900\(K\) while that of the surroundings is 300\(K\). The resistance at 900 \(K\) is \(5.68\pi \times {10^{ - 2}}\Omega \). Find the current in the wire. Stefan’s constant \( = 5.68 \times {10^{ - 8}}W{m^{ - 2}}{K^{ - 4}}\).

357133 A filament bulb (500 \(W\), 100 \(V\)) is to be used in a 230 \(V\) main supply. When a resistance \(R\) is connected in series, it works perfectly and the bulb consumes 500 \(W\). The value of \(R\) is

357134 Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating element should be _____ to _____ times of its initial length if the water is to be boiled in 15 minutes.

357135 Assertion :
When current through a bulb decrease by \(0.5 \%\), the glow of bulb decreases by \(1 \%\).
Reason :
Glow which is directly proportional to square of current.

357136 A wire of length 1.0 \(m\) and radius \({10^{ - 3}}m\) is carrying a heavy current and is assumed to radiate as a block body. At equilibrium its temperature is 900\(K\) while that of the surroundings is 300\(K\). The resistance at 900 \(K\) is \(5.68\pi \times {10^{ - 2}}\Omega \). Find the current in the wire. Stefan’s constant \( = 5.68 \times {10^{ - 8}}W{m^{ - 2}}{K^{ - 4}}\).