If two electric bulbs have $40\,W$ and $60\,W$ rating at $220\,V$, then the ratio of their resistances will be
Medium
Download our app for free and get started
(a) $P = \frac{{{V^2}}}{R} \Rightarrow $ $\frac{{{R_1}}}{{{R_2}}} = \frac{{{P_2}}}{{{P_1}}} = \frac{{60}}{{40}} = \frac{3}{2}$
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
- 1View SolutionThe internal resistance of a cell is the resistance of
- 2View SolutionThe equivalent resistance of the following infinite network of resistances is
- 3The electromotive force of a primary cell is $2\, volts$. When it is short-circuited it gives a current of $4$ amperes. Its internal resistance in $ohms$ isView Solution
- 4The current $I$ flowing through the given circuit will be $.....A$.View Solution
- 5Assertion : All electric devices shown in the circuit are ideal. The reading of each of ammeter $(a)$ and voltmeter $(V)$ is zero.View Solution
Reason : An ideal voltmeter draws almost no current due to very large resistance, and hence $(V)$ and $(a)$ will read zero.
- 6The potential difference between $A$ and $B$ in the Figure is .............. $V$View Solution
- 7View SolutionIn given circuit
- 8As shown in the schematic below, a rod of uniform cross-sectional area $A$ and length $l$ is carrying a constant current $i$ through it and voltage across the rod is measured using an ideal voltmeter. The rod is stretched by the application of a force $F$. Which of the following graphs would show the variation in the voltage across the rod as function of the strain $\varepsilon$ when the strain is small. Neglect Joule heating.View Solution
- 9In the arrangement shown in figure when the switch $S_2$ is open, the galvanometer shows no deflection for $l = L/2$. When the switch $S_2$ is closed, the galvanometer shows no deflection for $l = 5L /12$ . The internal resistance $(r)$ of $6\, V$ cell, and the $\mathrm{emf}$ $E$ of the other battery are respectivelyView Solution
- 10In a meter bridge, as shown in the figure, it is given that resistance $Y=12.5\, \Omega $ and that the balance is obtained at a distance $39.5\, cm$ from end $A$ (by jockey $J$) . After interchanging the resistances $X$ and $Y$, a new balance point is found at a distance $l_2$ from end $A$. What are the values of $X$and $l_2$ ?View Solution
