Electrical Field Strength

Electric Field - Physics A Level

By tyas ajeng

Practice

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Multiple Choice

Before a thunderstorm, the hairs on your head sometimes stand on end.

A hair with weight of 4.9 x 10^-3 N and charge 1.0 x 10^-12 C is supported by a force due to an electric field.

What is the electric field strength?

• 4.9 x 10³  N C^–1

• 4.9 x 10⁵ N C^–1

• 4.9 x 10⁶ N C^–1

• 4.9 x 10⁹ N C^–1

Multiple Choice

Which diagram represents the electric field of a negative point charge, -q ?

• A

• B

• C

• D

Multiple Choice

A positive charge and a negative charge of equal magnitude are placed a short distance apart. Which diagram best represents the electric field?

• A

• B

• C

• D

Multiple Choice

Which diagram shows the electric field between a positively charged metal sphere and an earthed metal plate?

• A

• B

• C

• D

Multiple Choice

In a uniform electric field, which statement is correct

• all charged particles experience the same force

• all chargd particles move with the same velocity

• all electric field lines are parallel

• all electric field lines are directed towards positive charges

Multiple Choice

The diagram shows a pair of metal plates 4.0 mm apart connected to a 9.0 V battery.

What is the electric field between the plates?

• 4.4 x 10^-4 NC^-1

• 3.6 x 10^-2 NC^-1

• 2.3 NC^-1

• 2.3 x 10³ NC^-1

Multiple Choice

Two horizontal parallel plate conductors are separated by a distance of 5.0 mm in air.

The lower plate is earthed and the potential of the upper plate is +50 V.

What is the electric field strength E at a point midway between the plates?

• 1.0 x 10⁴ Vm^-1 upwards

• 1.0 x 10⁴ Vm^-1 downwards

• 2.0 x 10⁴ Vm^-1 upwards

• 2.0 x 10⁴ Vm^-1 downwards

Multiple Choice

The diagram shows two parallel plates.

What is the electric field strength at point P?

• the same as that point Q

• twice that at point R

• half that at point Q

• one third that at point R

Multiple Choice

An electron of charge e is introduced between two metal plates a distance d apart.

A potential difference V is applied to the plates.

Which expression gives the electric force F on the electron?

• $$\frac{dV}{e}$$  

• $$\frac{eV}{d}$$  

• $$eVd$$  

• $$\frac{V}{ed}$$  

Multiple Choice

There is a force F acting on the charged particle due to the electric field.

The separation of the plates is doubled.

What will be the new force on the particle?

• $$\frac{F}{4}$$  

• $$\frac{F}{2}$$  

• $$F$$  

• 2 $$F$$   

Multiple Choice

Two parallel plates, a distance 25 mm apart, have a potential difference between them of 12 kV.

What is the force on an electron?

(given e = 1.60 x 10^-19 C)

• 4.8 x 10^-20 N

• 7.7 x 10^-20 N

• 4.8 x 10¹⁷ N

• 7.7 x 10^-14 N

Multiple Choice

See the diagram, what is the force experience by an electron in the electric field between the plates?

(given e = 1.60 x 10^-19 C)

• 2.6 x 10 ^-18 N

• 3.8 x 10 ^-18 N

• 2.6 x 10 ^-16 N

• 3.8 x 10 ^-16 N

Multiple Choice

An electrons are accelerated and then directed into the uniform electric field between two parallel plates in a vacuum.

What best decribes the shape of the path followed by electtrons?

• an upwards curve along a line that is part of a circle

• an unpwards curve along a line that is not part of a circle

• a downwards curve along a line that is part of a circle

• a downwards curve along a line that is part of a circle.

Multiple Choice

A very small oil drop of mass m carries a charge + q.

The potential difference across the plates is V and the separation is d.

THe weight of the drop is balanced by the electric force.

Which formula gives the charge on the drop?

• $$q=\frac{mgV\ }{d}$$  

• $$q=\frac{mgd}{V}$$  

• $$q=\frac{Vd}{mg}$$  

• $$q=\frac{V}{mgd}$$