class 12 ch 1
The magnitude of electric field due to a point charge 2q, at distance r is E. Then the magnitude of electric field due to a uniformly charged thin spherical shell of radius R wiith total charge q at a distance r/2 (r>>R) will be
2E
Soap bubble 'A' is given a negative charge and
soap bubble 'B' is given a positive charge, then
radius of bubble 'A' and 'B'
increases, increases
Two bodies are charged by rubbing one
against the other. During the process, one
becomes positively charged while the other
becomes negatively charged. Then mass of
each body
Changes slightly but the total mass remains
unchanged
Number of electrons in one coulomb of charge
will be
6. 25*10^18
The electric charge in uniform motion produce
Both electric and magnetic field
If a charge on the body is -1nC , then how
many number of excess electrons are present
on the body?
6.25*10^9
Five balls numbered 1 to 5 are suspended using
separate threads. Pairs (1, 2), (2, 4) and (4, 1)
show electrostatic attraction, while pair (2, 3)
and (4, 5) show repulsion. Therefore ball 1 must
be
Neutral
When a piece of polythene is rubbed with wool,
a charge of –2 × 10 C is developed on
polythene. What is the amount of mass which is
transferred to polythene?
11.38*10^(-19) kg
Two identical spheres carrying charges −9μC
and 5μC, respectively are kept in contact and
then separated from each other. Point out true
statement from the following. In each sphere
1.25*10^13 electrons are in excess
There are two charges +10μC having mass
10mg and +5μC having mass 5mg. The ratio
of their accelerations under coulomb's force
acting between them is:
1:2
Fg and Fe represents gravitational and
electrostatic force respectively between
protons situated at a distance 11μm. The ratio
of Fg/Fe is of the order of:
10^-36
Two charges each of 1μC are at a distance
1 cm apart in vacuum, the force between them
is
90N
Dielectric constant of pure water is 81. Its
permittivity will be in MKG units:
7.17*10^-10
Two small conducting spheres of equal radius
have charges +10μC and -20μC respectively
and placed at a distance R from each other
experience force F1. If they are brought in
contact and separated to the same distance,
they experience force F2. The ratio of F1 to F2 is
-8:1
Two charges placed in air repel each other by a
force of 10^(−4)
N. When oil is introduced
between the charges, the force on the charge
becomes 2. 5 × 10^(−5) N. The dielectric
constant of oil is:
4.0