Sign in
Please select an account to continue using cracku.in
↓ →
Join Our JEE Preparation Group
Prep with like-minded aspirants; Get access to free daily tests and study material.
The frequency ($$\nu$$) of an oscillating liquid drop may depend upon radius ($$r$$) of the drop, density ($$\rho$$) of liquid and the surface tension ($$s$$) of the liquid as: $$\nu = r^a \rho^b s^c$$. The values of $$a$$, $$b$$ and $$c$$ respectively are
Using dimensional analysis, the frequency $$\nu = r^a \rho^b s^c$$.
Dimensions of each quantity:
$$[\nu] = T^{-1}$$
$$[r] = L$$
$$[\rho] = ML^{-3}$$
$$[s] = MT^{-2}$$ (surface tension = force per unit length)
Writing the dimensional equation:
$$T^{-1} = L^a \cdot (ML^{-3})^b \cdot (MT^{-2})^c$$
$$T^{-1} = M^{b+c} \cdot L^{a-3b} \cdot T^{-2c}$$
Comparing powers of each dimension:
For $$M$$: $$0 = b + c$$ ... (i)
For $$L$$: $$0 = a - 3b$$ ... (ii)
For $$T$$: $$-1 = -2c$$ ... (iii)
From (iii): $$c = \frac{1}{2}$$
From (i): $$b = -c = -\frac{1}{2}$$
From (ii): $$a = 3b = 3 \times \left(-\frac{1}{2}\right) = -\frac{3}{2}$$
Therefore, $$(a, b, c) = \left(-\frac{3}{2}, -\frac{1}{2}, \frac{1}{2}\right)$$
The correct answer is Option 1.
Create a FREE account and get:
Predict your JEE Main percentile, rank & performance in seconds
Educational materials for JEE preparation
Ask our AI anything
AI can make mistakes. Please verify important information.
AI can make mistakes. Please verify important information.