### 20 Multiple Choice Static Electricity Practice Questions and Answers

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**Multiple Choice Static Electricity Practice Questions and Answer Keys – Static electricity** is an imbalance of electric charges within or on the surface of an object. The electric charge remains until the object loses it by means of an electric current releasing an electric charge.

This time **questionchemistry.com** will share examples of Static Electricity Problems and Discussions totaling 20 items complete with answer keys.

## 1 – 10 Physics Class 12 Static Electricity Problems and Discussion

1. It is known that the electric charge Q_{1 }positive and Q_{2} negative:

- (1) charge Q
_{1}attracting charge Q_{2} - (2) the coulomb force is proportional to Q
_{1}and Q_{2} - (3) the coulomb force is inversely proportional to the square of the distance between Q1 and Q2
- (4) the electric field strength in the middle between Q1 and Q2 is zero

the correct is ….

a. 1, 2, 3 and 4

b. 1, 2 and 3

c. 1 and 3

d. 2 and 4

e. 4

**Answer: B**

**Discussion **

Q1 = +q

Q2 = – q

**General equation**

F = k Q1Q2 / r²

- Positive charge Q1 attracts charge Q2
- The coulomb force (F) is proportional to Q1 and Q2
- The coulum force (F) is inversely proportional to the square of the distance (r²) between Q1 and Q2
- The electric field strength in the middle is not equal to zero.

**The answer is 1, 2, and 3**

2. Two similar and equal point charges qA = qB = 10 ^{–2}C at a distance of 10 cm from each other. The repulsive force experienced by the two charges (in Newtons) is…

a. 9.10^{–14 }

b. 9.10^{–9}

c. 9.10^{–5}

d. 9.10^{3}

e. 9.10^{7}

**Answer: E**

**Discussion:**

3. An object with a mass of 20 grams and a charge of q = + 0.5 C is suspended from a light string of negligible mass.

Just to the right of the object at a distance of 15 cm is placed a charge q’ = -1 C which causes the object’s position to be as shown below. If g = 10 ms^{–2}and k = 9.10^{9} Nm²C, the tension in the string is close to the value (in newtons)

a. 0.20

b. 0.24

c. 0.28

d. 0.32

e. 0.40

**Answer: C**

**Discussion:**

4. The strength of the electric field produced by an electric charge at a point depends on:

- (1) the magnitude of the load
- (2) the distance from the charge
- (3) load type
- (4) type of medium between charge and point

the correct is ….

a. 1, 2, 3 and 4

b. 1, 2 and 3

c. 1 and 3

d. 2 and 4

e. 4

**Answer: A**

**Discussion:**

Electric Field Strength Formula (E)

E = kq/r²

so depends on:

q or electric charge, magnitude and type of charge

and

r² = square of distance between charges

5. Two point charges are 5 cm apart as shown in the figure.

The electric field at point P is…

a. 27 N/C

b. 72 N/C

c. 270 N/C

d. 360 N/C

e. 720 N/C

**Answer: C**

**Discussion:**

#### Also read: Class 10 Physics Questions Semester 1 2013 Curriculum and the Answers

6. A particle of mass 0.3 g is tied with a massless thread. Then it is put into an electric field area of 500 N/C and hung, it turns out to form an angle as in the picture below. This situation can occur if the particle has a charge (in C) of

a. 1

b. 3

c. 3√ 2

d. 6

e. 6√ 2

**Answer: E**

**Discussion:**

7. Two particles A and B, each with a charge of +20 C and +45 C, are separated by a distance of 15 cm. If C is a point that lies between A and B such that the field strength at C is zero. The location of C from A (in cm) is….

a. 2

b. 3

c. 4

d. 6

e. 9

**Answer : D**

**Discussion:**

8. At each vertex of an equilateral triangle with sides 2√3 there is a positive charge q coloumb. The electric potential and field strength at the center of this triangle, with k as a constant, are, respectively?

a. 1/2 kq and 0

b. 1/2 kq and 3/2 kq

c. 2/3 kq and 3/2 kq

d. 0 and 3/2 kq

e. 0 and 2/3 kq

**Answer : D**

**Discussion:**

Distance O to A = Distance O to B = Distance O to C = 2 units of length. As a result, the resulting magnetic field is equal and the resultant magnetic field by the three charges will cancel each other out so that it can be written:

Eₒ = 0

Because electric potential is a scalar quantity, we simply add up the electric potential generated by each charge. Since the charge and distance are the same, let’s try to calculate first one charge (a)

Vₒₐ = kqₐ/rₒₐ

= kq/2

Then:

Vₒ = 3(kq/2)

= /₂ (kq/r)

9. A spherical conductor with a radius of 9 cm is given a charge of 6 mC. The magnitude of the electric field and electric potential at a point 3 cm from the center of the sphere is…

a. both zero

b. E = zero, V = 6. 10^{5}volt

c. E = 6. 10^{7}N/C, V = zero

d. E = 6. 10^{7}N/C, V = 6. 10^{5}volt

e. E = 6. 10^{7}N/C, V = 18. 10^{5}volt

**Answer: B**

**Discussion:**

10. A spherical conductor is given a charge Q = 3 C. The diameter of the ball is 20 cm. If a small charge q = 2 C is to be moved from the surface of the sphere to a point 5 cm from the center of the sphere, it takes a work of…

a. 2500 joules

b. 1300 joules

c. 500 joules

d. 25 joules

e. zero

**Answer: E**

### 11 – 20 Static Electricity Problems and Answer Key

11. Two parallel metal pieces 0.5 cm apart from each other are given opposite electric charges to a potential difference of 10000 Volts. If the electron charge is 1.6 x 10-19 C then the magnitude and direction of the coulomb force on an electron between the two plates is…

a. 0.8 x 10-7 N and above

b. 0.8 x 10-7 N and below

c. 3.2 x 10-13 N and above

d. 3.2 x 10-13 N and below

e. 12.5 x 1024 N and above

**Answer: C**

w = F . S

W = Ep

FS = Vq

Fr = Vq

F.0,5.10^{-2} = 10000. 1.6.10^{-19}

F = 3.2 . 10^{-13} N up due to positive charge

12. An electron (charge –1.6 x 10-19 C) moves from one point in space to another with a higher potential of 1 V. The kinetic energy gained by the electron in this displacement can be expressed as…

- (1) 1.6 x 10-19 Joule
- (2) 1 electron volt
- (3) 1.6 x 10-19 coulomb volts
- (4) 1 volt ampere

the correct is ….

a. 1, 2, 3 and 4

b. 1, 2 and 3

c. 1 and 3

d. 2 and 4

e. 4

**Answer: B**

w = FS

W = Ek

**So: 1, 2, 3 are correct**

13. An electron with a mass of 9.11×10 ^{–31}kg and electric charge –1.6 x10^{-19} C, separated from the cathode to the anode which is 2 cm apart. If the initial velocity of the electrons is 0 and the potential difference between the anode and cathode is 200 V, then the electrons will arrive at the anode with a speed of ….

a. 2.3 x 10^{5}m/s

b. 8.4 x 10^{6}m/s

c. 2.3 x 10^{7}m/s

d. 3 x 10^{7}m/s

e. 2.4 x 10^{8}m/s

**Answer: B**

**Discussion:**

W = Vq

W = Ek

Vq = Ek

200.1.6.10^{-19} = m. V^{2}

3,2.10^{-17 }= . 9.11.10^{-31 }. v^{2}

V = 8.4 . 10^{6}

14. The capacity of the capacitor can be reduced in the following ways….

- (1) the space between the plates is filled with oil
- (2) with a series pair of several capacitors
- (3) the distance between the two plates is reduced
- (4) the plate area is reduced.

the correct is ….

a. 1, 2, 3 and 4

b. 1, 2 and 3

c. 1 and 3

d. 2 and 4

e. 4

**Answer : D**

15. Three identical capacitors that are not initially charged will be connected to a 15 V battery.

If only one of them is connected to the 15 V battery, the energy stored in the capacitor is 3/2E. The energy that will be stored when the three capacitors are connected in series with the battery is…

a. E

b. E

c. E

d. 2 E

e. 4 E

**Answer: B**

c_{series} = 1/3 C

E_{2 }= 1/3 . 3/2 E

E_{2} = E

#### Also Read: Collection of Modern Physics Questions and Discussions

16. Three capacitors A, B, and C each with a capacity of 4F, 6F, and 12F are arranged in series and then connected with a voltage of 90V. If the electric charge of each capacitor is qA, qB, and qC then…

a. qC = 3 x qA

b. qA

c. qB = 0

d. qC = 1/3 x qA

e. qA = qB = qC

**Answer: E**

17. Three capacitors of 6 F, 12 F and 4 F are connected in series and then connected to an 8 volt source. The voltage across the 4 F capacitor is ….

a. 8.0 volts

b. 4.0 volts

c. 2.0 volts

d. 1.5 volts

e. 0.5 volts

**Answer: B**

**Discussion:**

18. Two capacitors with a capacity of C1 = 30 pF and C2 = 60 pF are connected in series, then connected to a voltage of 100 V, as shown in the figure. If the electric charge and potential difference on each capacitor are: Q1, Q2, V1 and V2 then….

- (1). Q1 = 2 x 10-9 C
- (2). Q2 = 2 x 10-9 C
- (3). V1 = 66.7 V
- (4). V2 = 33.3 V

the correct statement is….

a. 1, 2, 3 and 4

b. 1, 2 and 3

c. 1 and 3

d. 2 and 4

e. 4

**Answer: A**

1,2,3,4 true

20. A capacitor with a capacitance of 2.10^{-5}F which has been connected for some time to a potential difference of 500 V. Its two ends are connected to the ends of another capacitor with a capacitance of 3.10^{-5} uncharged F. The energy stored in the two capacitors is…

a. 0.25 J

b. 0.50 J

c. 1.00 J

d. 1.25 J

e. 1.50 J

**Answer : D**

**Discussion:**

E = CV^{2}

E = 5.10^{-5} 500^{2}

E = 1.25 Joule

#### Also Read: Multiple Choice Direct Current Circuit Problem [+Kunci Jawaban]

So this static electricity problem, hopefully it can help you in studying.

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