If the length of the filament of a heater is reduced by $10\%$, the power of the heater will
Medium
Download our app for free and get started
$P \propto \frac{1}{R}$ and $ R \propto l \Rightarrow P \propto \frac{1}{l}$
$ \Rightarrow \frac{{{P_1}}}{{{P_2}}} = \frac{{{l_2}}}{{{l_1}}} \Rightarrow \frac{{{P_1}}}{{{P_2}}} = \frac{{(100 - 10)}}{{100}} = \frac{{90}}{{100}}$$ \Rightarrow {P_2} = 1.11\,{P_1}$
$\%$ change in power = $\frac{{{P_2} - {P_1}}}{{{P_1}}} \times 100 = 11\% $
Download our appand get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Similar Questions
- 1Find the value of current from battery in the circuit ............... $A$View Solution
- 2In a meter bridge experiment, initially the jockey is at null point. Now resistance $R_1$ $\&$ $R_2$ is interchanged. Shift in the position of jockey is ................ $cm$View Solution
- 3In the figure a carbon resistor has bands of different colours on its body as mentioned in the figure. The value of the resistance is ................. $k \Omega$View Solution
- 4A cell, shunted by a $8 \; \Omega$ resistance, is balanced across a potentiometer wire of length $3 \; m$. The balancing length is $2 \; m$ when the cell is shunted by $4 \; \Omega$ resistance. The value of internal resistance of the cell will be $\dots \; \Omega .$View Solution
- 5In the given figure each plate of capacitance $C$ has partial value of chargeView Solution
- 6Potential difference across the terminals of the battery shown in figure is .................... $V$ ($r =$ internal resistance of battery)View Solution
- 7In the figure shown, if the internal resistance of the battery is $1\, ohm$, the reading of the ammeter will be ............... $A$View Solution
- 8In the given circuit the current flowing through the resisitance $20$ $\mathrm{ohms}$ is $0.3$ $\mathrm{ampere}$ while the ammeter reads $0.8$ $\mathrm{ampere}.$ What is the value of $R_1$? ................ $\mathrm{ohm}$View Solution
- 9Each element in the finite chain of resistors shown in the figure is $1\,\Omega $. A current of $1\, A$ flows through the final element. Then what is the potential difference $V$ across input terminals of the chain ............... $\mathrm{volt}$View Solution
- 10The ammeter reading in the following circuit will be .............. $A$View Solution
