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The resistance of the meter bridge AB in the given figure is [latex]4Omega[/latex]. With a cell of emf = 0.5 V and rheostat resistance Rh = [latex]2Omega[/latex] the null point is obtained at some point J. When the cell is replaced by another one of emf [latex]varepsilon =varepsilon _{2}[/latex] the same null point J is found for [latex]R_{h}=6Omega[/latex]. The emf [latex]varepsilon _{2}[/latex] is;

a. 0.3 V b. 0.5 V c. 0.4 V d. 0.6 V Answer: (a) Rh = \(\begin{array}{l}2\Omega\end{array} \) \(\begin{array}{l}i_{1}=\frac{6}{4+2}=1A\end{array} \)... View Article

An electromagnetic wave of intensity 50 Wm-2 enters in a medium of refractive index ‘n’ without any loss. The ratio of the magnitudes of electric fields, and the ratio of the magnitudes of magnetic fields of the wave before and after entering into the medium are respectively, given by

a. \(\begin{array}{l}\left [ \frac{1}{\sqrt{n}},\frac{1}{\sqrt{n}} \right ]\end{array} \) b. \(\begin{array}{l}\left [ \sqrt{n},\frac{1}{\sqrt{n}} \right ]\end{array} \) c. \(\begin{array}{l}\left [ \sqrt{n},\sqrt{n} \right ]\end{array}... View Article

There are two long co-axial solenoids of same length l. the inner and outer coils have radii r1 and r2 and number of turns per unit length n1 and n2 respectively. The ratio of mutual inductance to the self-inductance of the inner-coil is:

a. \(\begin{array}{l}\frac{n_{2}}{n_{1}}\frac{r_{2}^{2}}{r_{1}^{2}}\end{array} \) b. \(\begin{array}{l}\frac{n_{2}}{n_{1}}\frac{r_{1}}{r_{2}}\end{array} \) c. \(\begin{array}{l}\frac{n_{1}}{n_{2}}\end{array} \) d. \(\begin{array}{l}\frac{n_{2}}{n_{1}}\end{array} \) Answer: (d) Mutual Inductance= \(\begin{array}{l} = \mu _{0}n_{1}n_{2}R_{2}^{2}l\end{array}... View Article