Two electric bulbs marked $40\,W,$ $220\,V$ and $60\,W,\,\,220\,V$ when connected in series across same voltage supply of $220\,V,$ the effective power is $P_1$ and when connected in parallel, the effective power is $P_2.$ Then $\frac {P_1}{P_2}$ is
Medium
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 temperature at which thermal electric power of a thermo couple becomes zero is called
- 2A circuit containing five resistors is connected to a battery with a $12 \,V$ emf as shown in figure. The potential difference across $4 \,\Omega$ resistor is ........... $V$View Solution
- 3Eight resistances each of resistance $5\,\Omega $ are connected in the circuit as shown in figure. The equivalent resistance between $A$ and $B$ isView Solution
- 4Dimensions of a block are $1\,cm \times 1\,cm \times 100\,cm$. If specific resistance of its material is $3 \times {10^{ - 7}}\,ohm - m$, the resistance between the square faces isView Solution
- 5Drift speed of electrons, when $1.5\, A$ of current flows in a copper wire of cross section $5\, mm^2$, is $v$. If the electron density in copper is $9 \times 10^{28}\, m^3$ the value of $v$ in $mm/s$ is close to (Take charge of electron to be $= 1.6 \times 10^{-19}\, C$)View Solution
- 6In the circuit shown $E, F, G$ and $H$ are cells of $\mathrm{e.m.f.}$ $2\,V, 1\,V, 3\,V$ and $1\,V$ respectively and their internal resistances are $2\,\Omega , 1\,\Omega , 3\,\Omega$ and $1\,\Omega$ respectively.View Solution
- 7Resistance in the two gaps of a meter bridge are $10\, ohm$ and $30\, ohm$ respectively. If the resistances are interchanged the balance point shifts by.............. $cm$View Solution
- 8A voltmeter of resistance $1000\,\Omega$ is connected across a resistance of $500\, \Omega$ in the given circuit. What will be the reading of voltmeter .............. $V$View Solution
- 9Resistance of a carbon resistor determined from colour codes is $(22000 \pm 5 \%) \Omega$. The colour of third band must be :View Solution
- 10A potentiometer wire of length $1\,m$ and resistance $10\,\Omega$ is connected in series with a cell of $emf$ $2\,V$ with internal resistance $1 \,\Omega$ and a resistance box including a resistance $R$. If potential difference between the ends of the wire is $1\, mV$, the value of $R$ is ............. $\Omega $View Solution