Tag: static electricity

Questions Related to static electricity

Two metallic spheres, one hollow and the other solid, have same diameter. The hollow sphere will hold charge

  1. Same as the solid sphere

  2. 2 times as the solid sphere

  3. $\displaystyle\frac{1}{2}$ times as the solid sphere

  4. Zero


Correct Option: A
Explanation:

The capacity of the metallic sphere is proportional to the radius. It does not matter whether it is solid or hollow. Therefore the hollow sphere will hold same charge as the solid sphere.

Quantisation of charge implies

  1. charge does not exiet

  2. charge exists on particles

  3. there is a minimum permissible magnitude of charge

  4. charge can't be created


Correct Option: C
Explanation:

The word quantised means any quantity is an integral multiple of a minimum value and cannot have any value equal to decimal multiples.

The minimum charge that exists in nature is $1.6\times10^{-19}$ coulombs.
It is the positive value for one proton and negative for an electron.
Any charged body has a positive charge if electrons are less than needed and vice-versa.
Whatever may be the case, the magnitude of charge is always an integral multiple of $1.6\times10^{-19}$ coulombs.
Thus charge is quantised.

Charge on a body can be :

  1. $\displaystyle -1.3e$

  2. $\displaystyle 0.9e$

  3. $\displaystyle \pm 3e$

  4. $\displaystyle 1.5e$


Correct Option: C
Explanation:

Charge on a body is always $\displaystyle \pm e$, $\displaystyle \pm 2e$, $\displaystyle \pm 3e$. It can't be in fraction of e i.e 1.5e, 0.9e or -1.2e. The electronic charge is the minimum possible charge.

Charge on an electron is :

  1. $\displaystyle +e$

  2. $\displaystyle -e$

  3. $\displaystyle \pm e$

  4. All


Correct Option: B
Explanation:

Charge on an electron is -e. SInce, an atom can lose or gain an integer number of electron, so charge on an will be an integer multiple of e.

Charge on a body can be: 

  1. $\displaystyle \pm e$

  2. $\displaystyle \pm 2e$

  3. $\displaystyle \pm 3e$

  4. All


Correct Option: D
Explanation:

Charge on a body is always $\displaystyle \pm e$, $\displaystyle \pm 2e$, $\displaystyle \pm 3e$. It can never be in fraction of e. i.e. 1.5e or -1.2e.

A point charge $+q$ is placed at the centre of a cube of side L. The electric flux emerging from the cube is

  1. $\dfrac{q}{\varepsilon _0}$

  2. Zero

  3. $\dfrac{6qL^2}{\varepsilon _0}$

  4. $\dfrac{q}{6L^2\varepsilon _0}$


Correct Option: A
Explanation:

Since the charge is placed at the centre of the cube, so the electric flux lines move out equally from all sides of the cube. Thus the electric flux emerging from the cube is equal to $\dfrac{q}{\varepsilon _0}$.

Which is the elementary quantum of energy?

  1. Photon

  2. Electron

  3. Proton

  4. Neutron


Correct Option: A
Explanation:

Photon is the elementary quantum of energy.


Option A is correct.

Bulbs in street lightning are all connected in

  1. parallel

  2. series

  3. series-parallel

  4. end-to-end


Correct Option: A
Explanation:

Bulbs in street lightning are all connected in parallel.


Option A is correct.


For testing appliances, the wattage of test lamp should be

  1. very low

  2. low

  3. high

  4. any value


Correct Option: C
Explanation:

For testing appliances, the wattage of test lamp should be high, as higher watt lamps have lower resistance and will not blow up the testing appliacnces.

The additive nature of charge can be explained by the 

  1. Law of Conservation of Electric Charge

  2. Law of Quantisation of Electric Charge

  3. Law of Superposition of Electric Charge

  4. None of these


Correct Option: C
Explanation:

The additive nature of charge is one of the property of electric charge. The entire electric charge of a system is equal to the algebraic sum of electric charges located in the system. This is the law of superimposition of electric charge.