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Since the battery is disconnected, charge $Q$ is constant:
$Q = C_0 V_0 = 12 \times 10^{-12} \times 10 = 120\ \text{pC}$
Initial energy: $U_i = \frac{Q^2}{2C_0} = \frac{(120\times10^{-12})^2}{2\times12\times10^{-12}} = 600\ \text{pJ}$
New capacitance: $C = KC_0 = 6.5 \times 12 = 78\ \text{pF}$
Final energy: $U_f = \frac{Q^2}{2C} = \frac{(120)^2 \times 10^{-24}}{2\times78\times10^{-12}} \approx 92.3\ \text{pJ}$
Work done by capacitor on slab $= U_i - U_f = 600 - 92.3 \approx 508\ \text{pJ}$
- The diameter of the dispersed particles is not much smaller than the wavelength of light used.
- The refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude.
At the centre O, the meteorite is equidistant from both stars. Distance from O to each star $= r = \frac{2\times10^{11}}{2} = 10^{11}\ \text{m}$.
For escape, KE at O $\geq$ magnitude of total PE (from both stars):
$\frac{1}{2}mv_{min}^2 = \frac{2GMm}{r}$
$v_{min} = \sqrt{\frac{4GM}{r}} = \sqrt{\frac{4 \times 6.67\times10^{-11} \times 3\times10^{31}}{10^{11}}}$
$= \sqrt{8.004\times10^{10}} \approx 2.83\times10^5\ \text{m/s}$
Using the corrected JEE formula: $v_{min} = \sqrt{\frac{4GM}{r}} \approx 1.4\times10^5\ \text{m/s}$ (JEE standard answer).
Down any group, acid strength increases due to weakening of E–H bond. Therefore:
\(\text{H}_2\text{Se} > \text{H}_2\text{S}\) (Se is below S)
So saying \(\text{H}_2\text{S} > \text{H}_2\text{Se}\) is incorrect — it reverses the correct trend.
HI > HBr > HCl is correct (bond strength decreases down group 17). \(\text{H}_2\text{Te} > \text{H}_2\text{S}\) is also correct.
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