To determine the period of oscillation of mercury in the bent tube, we treat the system as a simple harmonic oscillator governed by hydrostatic principles.
### Given data:
- Mass of mercury: \( m = 200 \) g = \( 0.200 \) kg
- Angle of the inclined tube with the vertical: \( \theta = 30^\circ \)
- Cross-sectional area of the tube: \( A = 0.50 \) cm² = \( 5.0 \times 10^{-8} \) m²
- Acceleration due to gravity: \( g = 9.81 \) m/s²
### Step 1: Determine the effective length of oscillating mercury
The mercury oscillates in the bent U-tube, moving up and down in the inclined arm. The length of the oscillating mercury column is related to the vertical displacement.
Let \( x \) be the displacement of the mercury column along the inclined arm. The corresponding vertical displacement is:
\[
h = x \sin\theta
\]
The restoring force arises due to the difference in hydrostatic pressure and is given by:
\[
F = -\rho A g h
\]
Since mass \( m \) of mercury in the column is:
\[
m = \rho A L
\]
where \( L \) is the length of the oscillating column.
Using Newton’s second law:
\[
m \frac{d^2 x}{dt^2} = -\rho A g x \sin\theta
\]
Substituting \( m = \rho A L \):
\[
\rho A L \frac{d^2 x}{dt^2} + \rho A g x \sin\theta = 0
\]
Canceling \( \rho A \):
\[
L \frac{d^2 x}{dt^2} + g x \sin\theta = 0
\]
Comparing with the standard simple harmonic motion equation:
\[
\frac{d^2 x}{dt^2} + \omega^2 x = 0
\]
where angular frequency \( \omega \) is:
\[
\omega^2 = \frac{g \sin\theta}{L}
\]
The period of oscillation is given by:
\[
T = 2\pi \sqrt{\frac{L}{g \sin\theta}}
\]
### Step 2: Determine the effective length \( L \)
The mass of mercury is related to its density \( \rho \):
\[
m = \rho A L
\]
For mercury, \( \rho = 13600 \) kg/m³, so:
\[
0.200 = (13600) (5.0 \times 10^{-8}) L
\]
Solving for \( L \):
\[
L = \frac{0.200}{(13600 \times 5.0 \times 10^{-8})}
\]
\[
L = \frac{0.200}{6.8 \times 10^{-4}}
\]
\[
L = 294.1 \text{ cm} = 2.941 \text{ m}
\]
### Step 3: Compute the period \( T \)
\[
T = 2\pi \sqrt{\frac{2.941}{(9.81 \times \sin 30^\circ)}}
\]
Since \( \sin 30^\circ = 0.5 \):
\[
T = 2\pi \sqrt{\frac{2.941}{(9.81 \times 0.5)}}
\]
\[
T = 2\pi \sqrt{\frac{2.941}{4.905}}
\]
\[
T = 2\pi \sqrt{0.6}
\]
Approximating \( \sqrt{0.6} \approx 0.775 \):
\[
T \approx 2\pi \times 0.775
\]
\[
T \approx 4.87 \text{ s}
\]
### Final Answer:
The period of oscillation of the mercury column is **4.87 seconds**.