Electrostatics Practice Questions
KCSE (Kenya) · KCSE Physics · 146 free MCQs with instant results and detailed explanations.
146
Total
44
Easy
76
Medium
26
Hard
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Sample Questions from Electrostatics
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What happens to the electrostatic force between two charges if the distance between them is doubled?
A.
The force becomes four times stronger
B.
The force remains the same
C.
The force becomes half as strong
D.
The force becomes one fourth as strong
Show Answer & Explanation
Correct Answer: D
According to Coulomb's Law, the electrostatic force is inversely proportional to the square of the distance between the charges. If the distance is doubled, the force decreases by a factor of four, thus it becomes one fourth as strong.
Q2
Easy
Two charges, +5ยตC and -5ยตC, are placed 10 cm apart. What is the nature of the force acting between them?
A.
Attractive
B.
Repulsive
C.
Zero
D.
Dependent on medium
Show Answer & Explanation
Correct Answer: A
Since one charge is positive and the other is negative, they will exert an attractive force on each other. Opposite charges always attract.
Q3
Easy
If a plastic rod is rubbed with a wool cloth and becomes negatively charged, what does this indicate about the transfer of electrons?
A.
Electrons are transferred from the rod to the cloth
B.
Electrons are transferred from the cloth to the rod
C.
Protons move from the rod to the cloth
D.
No charge is transferred
Show Answer & Explanation
Correct Answer: B
When the plastic rod is rubbed with the wool cloth, electrons are transferred from the wool to the rod, giving the rod a negative charge. This indicates that the rod gains electrons.
Q4
Medium
Two point charges, +3 ฮผC and -3 ฮผC, are placed 0.5 m apart in a vacuum. What is the electric field intensity at the midpoint between the charges?
A.
0 N/C
B.
1.44 x 10^5 N/C
C.
2.5 x 10^5 N/C
D.
3.0 x 10^5 N/C
Show Answer & Explanation
Correct Answer: A
At the midpoint, the electric fields due to both charges are equal in magnitude but opposite in direction, thus they cancel each other, resulting in a net electric field of 0 N/C.
Q5
Medium
What happens to the electric potential energy of a system of two positive charges when they are moved farther apart?
A.
Increases
B.
Decreases
C.
Remains constant
D.
Becomes negative
Show Answer & Explanation
Correct Answer: B
The electric potential energy decreases when two like charges are separated because they repel each other, and energy is required to overcome this repulsive force.
Q6
Medium
A capacitor has a capacitance of 10 ฮผF and is charged to a potential difference of 50 V. What is the energy stored in the capacitor?
A.
0.025 J
B.
0.20 J
C.
0.50 J
D.
2.5 J
Show Answer & Explanation
Correct Answer: A
The energy stored in a capacitor is given by the formula U = 1/2 CVยฒ. Substituting C = 10 ฮผF and V = 50 V gives U = 0.025 J.
Q7
Medium
A dielectric material is inserted into a capacitor. Which of the following statements is true regarding the capacitance?
A.
Capacitance decreases
B.
Capacitance remains unchanged
C.
Capacitance increases
D.
Capacitance becomes zero
Show Answer & Explanation
Correct Answer: C
Inserting a dielectric material into a capacitor increases the capacitance because it reduces the electric field within the capacitor and allows for more charge storage.
Q8
Hard
A charged particle experiences a force of 10 N in an electric field of strength 5 N/C. What is the charge of the particle?
A.
2 C
B.
0.5 C
C.
5 C
D.
0.2 C
Show Answer & Explanation
Correct Answer: A
The force on a charged particle in an electric field is given by F = qE, where F is the force, q is the charge, and E is the electric field strength. Rearranging gives q = F/E. Therefore, q = 10 N / 5 N/C = 2 C.
Q9
Hard
Two point charges, +3 ยตC and -3 ยตC, are placed 0.5 m apart in a vacuum. What is the magnitude of the electric field at the midpoint between the charges?
A.
1.44 ร 10^4 N/C
B.
1.80 ร 10^4 N/C
C.
2.00 ร 10^4 N/C
D.
1.20 ร 10^4 N/C
Show Answer & Explanation
Correct Answer: B
The electric field due to a point charge is given by E = k|q|/rยฒ. At the midpoint, the distance from each charge is 0.25 m. Calculate E from each charge and sum their contributions (E1 from +3 ยตC and E2 from -3 ยตC), which results in E = 1.80 ร 10^4 N/C.
Q10
Hard
A charged rod is brought close to a neutral metallic sphere. The sphere gets polarized. Which of the following describes the charge distribution on the sphere?
A.
The side closest to the rod becomes positively charged.
B.
The entire sphere becomes negatively charged.
C.
The side farthest from the rod becomes positively charged.
D.
The sphere remains neutral with no charge distribution.
Show Answer & Explanation
Correct Answer: A
When a charged rod is brought near a neutral metallic sphere, the electrons in the sphere are attracted to the rod (if it's positive) or repelled (if it's negative). This results in the side closest to the rod becoming negatively charged, while the side farthest becomes positively charged. Therefore, option A correctly identifies the polarization effect.
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Electrostatics โ KCSE (Kenya) KCSE Physics Practice Questions Online
This page contains 146 practice MCQs for the chapter Electrostatics in KCSE (Kenya) KCSE Physics. The questions are organized by difficulty โ 44 easy, 76 medium, 26 hard โ so you can choose the right level for your preparation.
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