The work done in increasing the size of a soap film for \(10~ \mathrm{cm} \times 6~ \mathrm{m}\) to \(10~ \mathrm{cm} \times 11~ \mathrm{m}\) is \(3\times 10^{-4}\) J. The surface tension of the film is:
1. \(1.0 \times10^{-2}\) N/m
2. \(6.0 \times 10^{-2}\) N/m
3. \(3.0 \times 10^{-2}\) N/m
4. \(1.5 \times 10^{-2}\) N/m
A parallel plate condenser is filled with two dielectrics as shown in the figure. The area of each plate is \(A~\text m^2\) and the separation is \(d\) meter. The dielectric constants are \(K_1\) and \(K_2\) respectively. Its capacitance in farad will be:
1. \(\frac{2\varepsilon_{_0}A}{d}\Big(\frac{K_1+K_2}{K_1K_2}\Big)\)
2. \(\frac{2\varepsilon_{_0}A}{d}\Big(\frac{K_1K_2}{K_1+K_2}\Big)\)
3. \(\frac{\varepsilon_{_0}A}{d}\Big(\frac{K_1+K_2}{2K_1K_2}\Big)\)
4. \(\frac{\varepsilon_{_0}AK_1K_2}{2(d_2K_1+d_1K_2)}\)
1. | monoatomic |
2. | polyatomic |
3. | mixture of diatomic and polyatomic molecules |
4. | diatomic |