# WAEC GCE Physics Questions and Answers 2020/2021 (Essay and Objectives)

WAEC GCE Physics questions and answers 2020. Welcome to 2020 WAEC Physics questions and Answers. You will find WAEC GCE Physics Objective and Theory Answers, WAEC Physics Essay 2020, WAEC GCE 2020 Physics and the tips you need to pass your WAEC GCE Physics examination at ease.

## WAEC Physics Objectives And Essay Answers 2020

1. Which electrical device does the diagram above illustrate?

(a) a.c. generator

(b) a.c. motor

(c) d.c generator

(d) d.c motor

2. A simple barometer is constructed using a liquid Q1 of density 16.2g/cm3. Calculate the least length of the tube to be used to measure pressure of 1.5 atmospheres. (Density of mercury = 13.6g/cm3, 1 atmosphere = 76.0cm of mercury)

(a) 1358 mm

(b) 957 mm

(c) 760 mm

(d) 638 mm

3. A bar AB is balanced horizontally on two knife edges as illustrated in the diagram above. Determine the weight of the bar.

(a) 10.0 N

(b) 20.0 N

(c) 40.0 N

(d) 50.0 N

4. To obtain a virtual, erect and magnified image from a thin converging lens, an object must be placed

(a) Between the focus and the lens

(b) at the focus

(c) between the focus and twice the focal length

(d) beyond twice the focal length

5. The diagram above represents a transverse travelling wave. Which two points are 180o out of phase?

(a) A and E

(b) B and D

(c) C and F

(d) D and H

6.  Two objects P and Q of masses 100 kg and 20 kg respectively are 1.2 m apart on a horizontal surface. Calculate the net gravitational force acting on Q. (G=6.67 x 10-1 Nm2kg-2)

(a) 1.11 x 10-7 N towards P

(b) 1.11 x 10-7 N towards Q

(c) 9.26 x 10-8 N towards P

(d) 9.26 x 10-8 N towards Q

7. The primary of a transformer has 100 turns and its secondary has 200 turns. If the voltage at the primary is 100 V. determine the voltage at the secondary

(a) 50 V

(b) 100 V

(c) 200 V

(d) 400 V

8. In the diagram illustrated above, a block of mass M is at rest on a plane inclined at an angle θ to the horizontal. As θ increases, the velocity ratio of the plane

(a) Increases

(b) decreases

(c) remain the same

(d) decreases and later increases

9. When the speed of a car is halved, is kinetic energy is

(a) Doubled

(b) quartered

(c) halved

10. A wire of length 400cm is stretched between two fixed pointed. When plucked its fundamental frequency is 150 Hz. Calculate the speed of the wave produced.

(a) 250 ms-1

(b) 625 ms-1

(c) 1200 ms-1

(d) 1500 ms-1

11. The diagram above illustrates a waveform. Determine the number of wavelengths in it.

(a) 4

(b) 3½

(c) 2½

(d) 2

12. A resistor with fixed resistance value is called a

(a) Restance box

(b) standard resistor

(c) shunt

(d) multiplier

13. Which of the following statements is not an advantage of an alkaline accumulator?

(a) The electrolyte does not need attention

(b) it can be recharged

(c) it has low internal resistance

(d) it has a much longer life than lead-acid accumulator

14. The diagrams above illustrate the wire connections to a three-pin plug. The wires P, Q and R respectively are:

(a) Live, neutral and earth

(b) neutral, earth and live

(c) earth, live and neutral

(d) earth, neutral and live

15. Which of the following statement about, parallel plate capacitors is/are correct? I. Capacitance of the capacitor is inversely proportional to the distance between the plates II. Capacitors can filter a, c, signals from d, c, III. Capacitors can store charges.

(a) I only

(b) I and II only

(c) II and III only

(d) I, II and III

16. A circuit contains three ammeters A1, A2 and A3 with readings of A2 and A3 shown as indicated in the diagram. Determine the reading of A1.

(a) 2 A

(b) 3 A

(c) 5 A

(d) 8 A

17. Which of the following statements about magnetic lines of force is not correct? They

(a) Pass through even non-magnetic materials

(b) run from the north pole to be shorted

(c) are in a state of tension and tend to be shored

(d) intersect one another.

18. In which of the following activities is an induction coil not useful?

(a) Investigation of high voltages

(b) Study of electric discharge

(c) Operation of X-ray tubes

(d) A.C. power transmission

19. In a series R-L-C circuit, R=10Ω, X = 4Ω and XL = 9Ω. The impedance of the circuit is

(a) 4.1Ω

(b) 5.0Ω

(c) 10.8Ω

(d) 11.2Ω

20. A student uses two compass needles to investigate the magnetic field around a bar magnet. Which of the following diagrams show the correct directions of the needles?

21. Which of the following particles may be emitted in a process of natural radioactivity?

(a) α=particles and β-particles

(b)α-particles and X-rays

(c) β-particles and X-rays

(d) λ-rays and X-rays

22. Which of the following situations is photoelectric effect employed? I. Automatic devices for switching on light at dusk II. Automatic doors in departmental stores III. Automatic devices for switching on air conditioners IV. Automatic voltage stabilization

(a) I, II and IV only

(b) I, III and IV only

(c) III and IV only

(d) I and II only

23. Which of the following radiations has the longest wavelength?

(a) Gamma ray

(c) Infrared ray

(d) X-ray

23. In which of the following fields is radioisotopes not used?

(a) Medicine

(b) Oil industry

(c) Agriculture

(d) Weather forecast

24. A nuclide is represented by 7032B. Determine its neutron-proton ratio

(a) 0.5

(b) 0.8

(c) 1.2

(d) 1.5

## WAEC GCE Physics Essay 2020

The above questions are not exactly 2020 WAEC Physics questions and answers but likely WAEC Physics repeated questions and answers. 