MCQ
A soap bubble is given negative charge, its radius will:
- AIncrease
- BDecrease
- CRemain unchanged
- DFluctuate
✓
Answer
- Increase
Explanation:
The charge will be distributed uniformly over the surface of the bubble by symmetry.
As we know, they want to step much farther apart, as charges repel, the only path outward, taking with them the soap surface.
At the same point, the rise in the restored force of the soap film (surface tension) would be equal and contrary to the electrostatic force, which will result in a new (larger) radius of equilibrium.
Because of the ionic similarities, this can happen to both positive and negatively charged bubbles.Therefore, when a negative charge is given to the soap bubble, then its radius will increase.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A transformer increases ac voltage supply from 220 V to 2200 V. If there are 2000 turns in the second- ary coil, then number of turns in the primary coil is:
The charge on a hole is equal to the charge of
|
(a) Zero |
(b) Proton |
(c) Neutron |
(d) Electron |
Angle between equipotential surface and lines of force is
|
(a) Zero |
(b) 180° |
(c) 90° |
(d) 45° |
The plate resistance of a triode is 2.5 × 104 W and mutual conductance is 2 × 10–3 mho. What will be the value of amplification factor
|
(a) 50 |
(b) 1.25 × 107 |
(c) 75 |
(d) 2.25 × 107 |
The particle that possesses half integral spin as
|
(a) Photon |
(b) Pion |
(c) Proton |
(d) K-meson |
Resistors of 1, 2, 3 ohm are connected in the form of a triangle. If a 1.5 volt cell of negligible internal resistance is connected across 3 ohm resistor, the current flowing through this resistance will be
|
(a) 0.25 amp |
(b) 0.5 amp |
(c) 1.0 amp |
(d) 1.5 amp |
The number of neutrons released when 
undergoes fission by absorbing 
and (
are formed, is
|
(a) 0 |
(b) 1 |
(c) 2 |
(d) 3 |
Light from the constellation Virgo is observed to increase in wavelength by 0.4%. With respect to Earth the constellation is
|
(a) Moving away with velocity 1.2 × 106 m/s |
|
(b) Coming closer with velocity 1.2 × 106 m/s |
|
(c) Moving away with velocity 4 × 106 m/s |
|
(d) Coming closer with velocity 4 × 106 m/s |
The dimension of the magnetic field intensity B is
|
(a) |
(b) |
(c) |
(d) |
The working principle of dynamo is based on :