Please answer all questions, please help this is my last question to post 1.A ch

Question

Please answer all questions, please help this is my last question to post

1.A charge of -5.40 C is located on the x axis at x = 2.40 cm. A charge of -5.40 C is located on the x axis at x = -2.40 cm. Find the electric field on the y axis at y = 6.50 cm.

Give only the magnitude of the field.

Find the force on a 1.43 nC charge on the y axis at y = 6.50 cm. Give only the magnitude of the force.

2.An electron (mass m = 9.11E-31 kg) is accelerated in the uniform field E (E = 1.78E+4 N/C) between two parallel charged plates. The separation of the plates is 1.40 cm. The electron is accelerated from rest near the negative plate and passes through a tiny hole in the positive plate, as seen in the figure below. ?Show that the gravitational force can be ignored by calculating the ratio of the gravitational to the electric force. Calculate that ratio.

3.Two large parallel copper plates are 15.00 cm apart and have a uniform electric field between them. An electron is released from the negative plate at the same time that a proton is released from the positive plate. Neglect the force of the particles on each other and find their distance from the positive plate when they pass each other.

Explanation / Answer

2.We know that the force F=charge(q)*Electric field.

F electrostatic = q*E = 1.6*10-19 * 1.78*104 = 2.848*10-15 N

F gravity = m g = 9.11*10-31 * 9.8 = 8.9278*10-30N
The ratio of this force is given by,
F gravity/F electrostatic = 3.13*10-15

The gravitational force is very low. Hence it can be neglected.

3. We know that the mass of proton is 1836 times greater than that of electron. Since the mass is 1836 times greater we can assume that the velocity would be in the ratio of 1 : 1836 for proton and electron.

The proton and the electron will meet at a particular time. Let as assume the time be t. Before meeting the proton will cover a distance. Consider x be the distance covered by proton .Let us consider that the proton starts the journey from the plate, then x is proportional to 1 and the remaining distance is 15 - x.

The remaining distance will be proportional to 1836.
So dividing, x/(15 - x) = 1/1836
Or, 1836x = 15-x

1837x=15
So, x = 15/1837 = 0.008 cm
So the proton and electron pass each other at a distance 0.008 cm from the proton released plate.

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