Question 11

A polythene piece rubbed with wool is found to have a negative charge of 3 × 10^{−7} C.

(a) Estimate the number of electrons transferred (from which to which?)

(b) Is there a transfer of mass from wool to polythene?

Answer

(a) When polythene is rubbed against wool, a number of electrons get transferred from wool to polythene. Hence, wool becomes positively charged and polythene becomes negatively charged.

Amount of charge on the polythene piece, q = −3 × 10^{−7} C

Amount of charge on an electron, e = −1.6 × 10^{−19} C

Number of electrons transferred from wool to polythene = n

n can be calculated using the relation, q = ne

=

= 1.87 × 10^{12}

Therefore, the number of electrons transferred from wool to polythene is 1.87 × 10^{12}.

(b) Yes. There is a transfer of mass occur. This is because an electron has mass,

as we know

m_{e} = 9.1 × 10^{−3} kg

Total mass transferred from wool to polythene,

m = m_{e} × n

= 9.1 × 10^{−31} × 1.85 × 10^{12}

= 1.706 × 10^{−18} kg

Hence, a negligible amount of mass is transferred from wool to polythene.

- Q:-
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- Q:-
What is the force between two small charged spheres having charges of 2 x 10

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^{3}îN/C.(a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane?

(b) What is the flux through the same square if the normal to its plane makes a 60° angle with the x-axis?

- Q:-
Two point charges q

_{A}= 3 μC and q_{B}= −3 μC are located 20 cm apart in vacuum.(a) What is the electric field at the midpoint O of the line AB joining the two charges?

(b) If a negative test charge of magnitude 1.5 × 10

^{−9}C is placed at this point, what is the force experienced by the test charge? - Q:-
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^{3}N/C and points radially inward, what is the net charge on the sphere? - Q:-
A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 μC/m

^{2}.(a) Find the charge on the sphere.

(b) What is the total electric flux leaving the surface of the sphere?

- Q:-
Two charges 5 x 10

^{-8}C and -3 x 10^{-8}C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero. - Q:- A 100 Ω resistor is connected to a 220 V, 50 Hz ac supply.

(a) What is the rms value of current in the circuit?

(b) What is the net power consumed over a full cycle? - Q:-
A 600 pF capacitor is charged by a 200 V supply. It is then disconnected from the supply and is connected to another uncharged 600 pF capacitor. How much electrostatic energy is lost in the process?

- Q:-
A point charge causes an electric flux of −1.0 × 10

^{3}Nm^{2}/C to pass through a spherical Gaussian surface of 10.0 cm radius centered on the charge.(a) If the radius of the Gaussian surface were doubled, how much flux would pass through the surface?

(b) What is the value of the point charge?

- Q:-
A silver wire has a resistance of 2.1 Ω at 27.5 °C, and a resistance of 2.7 Ω at 100 °C. Determine the temperature coefficient of resistivity of silver.

- Q:-
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^{-8}C and -3 x 10^{-8}C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero. - Q:- ">
Determine the current in each branch of the network shown in figure

- Q:-
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^{3}N/C and points radially inward, what is the net charge on the sphere? - Q:-
A regular hexagon of side 10 cm has a charge 5 µC at each of its vertices. Calculate the potential at the centre of the hexagon.

- Q:-
that the capacitance of a spherical capacitor is given by

where

">*r*1 and*r*2 are the radii of outer and inner spheres, respectively.A spherical capacitor consists of two concentric spherical conductors, held in position by suitable insulating supports (Figure). Show

that the capacitance of a spherical capacitor is given by

where

*r*1 and*r*2 are the radii of outer and inner spheres, respectively. - Q:- Two long and parallel straight wires A and B carrying currents of 8.0 A and 5.0 A in the same direction are separated by a distance of 4.0 cm. Estimate the force on a 10 cm section of wire A.">
Two long and parallel straight wires A and B carrying currents of 8.0 A and 5.0 A in the same direction are separated by a distance of 4.0 cm. Estimate the force on a 10 cm section of wire A.

- Q:- The electrostatic force on a small sphere of charge 0.4 μC due to another small sphere of charge − 0.8 μC in air is 0.2 N.
(a) What is the distance between the two spheres?

(b) What is the force on the second sphere due to the first?

">The electrostatic force on a small sphere of charge 0.4 μC due to another small sphere of charge − 0.8 μC in air is 0.2 N.

(a) What is the distance between the two spheres?

(b) What is the force on the second sphere due to the first?

- Q:-
A 600 pF capacitor is charged by a 200 V supply. It is then disconnected from the supply and is connected to another uncharged 600 pF capacitor. How much electrostatic energy is lost in the process?

Ankit Yadav
2019-06-21 06:45:55

Thanks

Anushka
2019-06-09 08:36:06

Thank you, I got it ð

2019-01-04 23:30:29

me = 9.1 Ã 10â3 kg y sahi hai

Ujjwal
2018-09-22 19:09:40

How u get Me value there

Aaishu
2018-05-16 20:33:49

I sincerely apologise to have given an incorrect comment previously. Regards.

Aaishu
2018-05-16 20:31:41

There's also a part (c) in the question. Please check. Regards

Savithri
2018-03-30 11:11:37

Its totally wrong

DEVYANI
2018-03-24 20:54:19

no due to wrong multiplication

Why
2018-03-05 21:25:20

nooooo

Debosmit
2017-02-08 21:50:19

Why is n is having a fractional value when \'n\' must always be a whole number according to quantization theory? Please explain the fault in the numerical.

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