Millikan's Oil Drop Experiment

Q.

How do you know if the electric potential is positive or negative?

Q.

Is electric potential a scalar or a vector quantity?

Q.

Calculate the electric field intensity which would be just sufficient to balance the weight of a particle of charge $-10\mu c$and mass$10mg$. [take$g=10m{s}^{-2}$].

Q.

(a) Calculate the number of electrons which will together weigh one gram.

(b) Calculate the mass and charge of one mole of electrons.

Q. It is required to hold equal charges Q in equilibrium at the corners of a square. What charge when placed at the centre of the square will do this

Q.

A certain particle carries 2.5 × ${10}^{–16}$ C of static electric charge. Calculate the number of electrons present in it.

Q. The value of e/m for cathode rays

1. remains constant irrespective of the nature of gas.
2. varies as the atomic number of the gas in the discharge tube changes
3. has the smallest value when the discharge tube is filled with hydrogen
4. Varies as the atomic number of the element forming the cathode in the discharge tube changes

Q.

What do you mean by zero potential?

Q. Millikan’s oil drop experiment was conducted to measure the value of the:

1. e/m ratio
2. Charge ‘e’ on an electron
3. Mass of a proton
4. Mass of an electron

Q.

The minimum charge on an object is __________.

Q. In a Millikan's oil drop experiment, the charge on an oil drop is calculated to be $-6.4\times {10}^{-19}\text{C}$. The number of excess electrons on the drop is:

1. $3.9$
2. $5$
3. $6$
4. $4$

Q. Charge on a proton is $1.6\times {10}^{-19}\text{C}$ and its mass is calculated to be equal to $1.67\times {10}^{-27}\text{kg}$. Then $e/m$ for proton is:
($e:\text{Charge};m:\text{Mass}$)

1. Less than $e/m$ value for electron
2. Equal to $e/m$ value for neutron
3. Equal to $e/m$ value for electron
4. Greater than $e/m$ value for electron

Q. In Milikan's oil drop experiment, which of the following charges can exist on an oil drop?
Charge on electron e = $-1.6\times {10}^{-19}\text{C}$

1. $2.8\times {10}^{-19}\text{C}$
2. $3.2\times {10}^{-19}\text{C}$
3. $8.0\times {10}^{-19}\text{C}$
4. $11.2\times {10}^{-19}\text{C}$

Q. In Millikan’s oil drop experiment the forces acting on the oil drop when oil drop is moving are gravitaional force, electrostatic force and viscous drag.
Which force will stop acting on the oil drop if it's speed is reduced to zero

1. Gravitational Force
2. Electrostatic Force
3. Viscous Drag
4. All of the above

Q.

The quantum of electric charge in e s u?

1. $4.78\times {10}^{-10}$

2. $+1.6\times {10}^{-19}$

3. $2.99\times {10}^9$

4. $-1.6\times {10}^{-19}$

Q.

In Milikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static electric charge on the oil drop is –1.282 × ${10}^{–18}$ C, calculate the number of electrons present on it.

Q. The nature of anode rays depends upon:

1. Nature of electrode
2. Nature of residual gas
3. Nature of discharge tube
4. All of the above

Q. An oil drop has a charge of $6.4\times {10}^{-19}$ C. Find out the number of electrons in the oil drop.

1. 2
2. 3
3. 4
4. 8

Q. In Millikan’s oil drop experiment, the forces acting on a moving drop of oil are:

1. Gravitational force and viscous drag
2. Electrostatic force and acceleration force
3. None of the above
4. Gravitational force, electrostatic force and viscous drag

Q. In the oil drop experimant, charge on electron came out to be $-1.6\times {10}^{-19}\text{C}$. From Thomson's experiment, $e/m$ value for electron calculated was $1.758820\times {10}^{11}\text{C/kg}$. Find the mass of the electron.
(Given: $e$ is the magnitude of charge on electron)

1. $1.67\times {10}^{-27}\text{kg}$
2. $9.1\times {10}^{-31}\text{kg}$
3. $9.1\times {10}^{-28}\text{kg}$
4. $1.67\times {10}^{-31}\text{kg}$

Q. Millikan's oil drop experiment was conducted to find:

1. Mass of an electron
2. Charge on an electron
3. Mass of proton
4. Charge of a proton

Q. The increasing order of the values of e/m (charge/ mass) is :

1. n, α, p, e
2. e, p, n, α
3. n, p, α, e
4. n, p, e, α

Q. Assume that a box full of electrons had a total charge of $-96368\text{C}$. The number of moles of eletcrons present inside the box is
$\text{Given}:e=-1.6\times {10}^{-19}\text{C}$

Q.

How to calculate static pressure?

Q. For the production of y L H2 at STP at cathode, cost of electricity is x, then cost of production of y L O2 at STP at anode will be

Q.

Give the name of the scientist who discovered the electron. describe the experiment conducted for the discovery of electrons. how are the mass and charge of electrons determined?

Q. In Millikan's oil drop experiment, which of the following force(s) act(s) on the oil drop?

1. Gravitational force
2. Electrostatic force
3. Viscous drag
4. All of the above

Q. In Millikan’s oil drop experiment, the oil drop stops if:

1. Electrostatic force = viscous force
2. Magnetic force = viscous force
3. Electrostatic force = magnetic force
4. Electrostatic force = gravitational force

Q. An oil drop has 7.99 $\times$ ${10}^{-19}$ C charge. The number of electrons that the oil drop has is .

1. 2
2. 5
3. 3

Q. As a result of Millikan's oil drop experiment, value of electronic charge was found to be approximately equal to:

1. $-1.6\times {10}^{-19}\text{C}$
2. $1.6\times {10}^{-19}\text{C}$
3. $3.2\times {10}^{-19}\text{C}$
4. $-3.2\times {10}^{-19}\text{C}$