
- **Option A:** In a purely capacitive circuit, the voltage (V) lags the current (I) by 90°. Therefore, **A-I** is correct.
- **Option B:** In a purely inductive circuit, the voltage (V) leads the current (I) by 90°. Therefore, **B-II** is correct.
- **Option C:** In an LCR series circuit at resonance, the inductive reactance (XL) equals the capacitive reactance (XC), resulting in a purely resistive behavior where the voltage and current are in phase. Therefore, **C-III** is correct.
- **Option D:** In a general LCR series circuit, the voltage and current are out of phase by an angle θ, which depends on the relative values of XL and XC. Therefore, **D-IV** is correct.
**Answer:** A-I, B-II, C-III, D-IV (Option 4)
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,

What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)