NECO 2020 PHYSICS QUESTIONS AND ANSWERS

PHYSICS OBJ

1-10: BCBDBDCDCD

11-20: DACBEBABDE

21-30: CDDDABBBAC

31-40: CDAEBBCCDC

41-50: BEEBDBAEEC

51-60: DDCDADDEBD

=============================

 

 

 

(1ai)

[Choose ANY ONE]

-Printer

-Photocopy machine

-Label maker

-Document scanner

 

(1aii)

Sterilizer

 

(1b)

Draw the diagram.

 

(1c)

I = 1.26A

t = 4800s

m = ?

Z = 3.3×10^-⁴gc-¹

m = ZIt

m = 3.3×10^-⁴×1.26×4800

m = 1.996g

 

 

=============================

 

(3a)

Velocity is defined as the rate of change of distance moved in a specific direction or the rate of change of displacement.

 

(3b)

U = 0m/a

V = 20ms-¹

t1 = 20s

t2 = 30s

t3 = 10s

 

Draw the diagram

 

 

=============================

 

(5a)

[Choose ONLY ONE]

-They are both scalar quantity.

-They are both connected with work.

 

(5b)

R0 = 25ohms

R100 = 100ohms

R = ?

Tita = 67°c

Tita= Rtita-R0/R100-25 × 100

67 = R – 25/100 – 25 × 100

67 = (R0 – 25)/75 × 100

R0 – 25 = 67 × 75/100

Rtita – 25 = 50.25

Rtita = 50.25+25

Rtita = 75.25ohms

 

 

=============================

 

((9a)

It simply means that the ratio of resistance and impedance is 1 and the maximum power is obtained in such circuit.

 

(9b)

V² = Vr² + Vc²

15² = 12² + Vc²

225 – 144 = Vc²

V = √81

Vc = 9

 

 

=============================

 

(10a)

(i) Weight

(ii) Upthrust.

(iii) Viscous force.

 

(10b)

Both viscous force and upthrust acts in upward direction while weight act downward in order to balance the force

 

=============================

 

(11i)

 

4 A 12 1

He + Be –> X + Y + Z

2 A B C

 

A = 9

B = 6

C = 1

 

(11ii)

Z = 0

e ie Beta particles.

-1

 

(11iii)

Nuclear fusion

W = v + u

 

 

=============================

 

(12a)

(i) Friction.

(ii) Upthrust.

 

(12aii)

(i) Force causes motion

(ii) Force causes stress/strain

 

(12b)

Draw the diagram [https://i.imgur.com/j8jNZmi.jpg]

 

(12c)

Draw the diagram [https://i.imgur.com/j8jNZmi.jpg]

(i) Taking moment about pivot

CW moment = ACW moment

36×25 = X×15

X = 36×25/15 = 60g

 

(ii)

Draw the diagram[https://i.imgur.com/j8jNZmi.jpg]

60 × X = 36 × (30 – X)

60X = 1080 – 36x

96X = 1080

X = 1080/96 = 11.25

Distance = 11.25 from the zero end.

 

 

=============================

 

(13ai)

(i) Dew

(ii) Mist

 

(13aii)

(i) Both require the supply of heat.

(ii) Vapour is expelled when both processes occur.

 

(13b)

An object initially at a height, say H has a tiny potential energy. As it falls and now at a height say h, the potential energy reduces and kinetic energy increases. The kinetic energy because it is equal to the P.E at height H when the object just strikes the ground.

NB: At any point, mechanical energy is conserved.

 

(13ci)

Given V.R = 5, Load L = 500N

Workdone against friction

= Total workdone – work output by system.

= 7200 – (500 × 12)

= 7200 – 6000

= 1200J

 

(13cii)

Efficiency = work output/work input × 100%

= 6000/7200 × 100%

= 83.33%

 

 

=============================

 

(14a)

Given y = Asin2pie(t/T – x/lander)

 

(i)

T represents period.

Lander represents wavelength.

 

(ii)

T = 2pie/w

T = 1/f

 

(14bi)

(i) Microscope.

(ii) Telescope.

 

(14bii)

Refraction involves two media, while reflection involves one medium.

 

(14ci)

Frequenxy of wave f = v/lander

= 0.6/0.04 = 1.5 Hertz

 

(14cii)

Refractive index of water = speed in deep water/speed in shallow water.

= 0.8/0.6 = 4/3

 

 

 

 

(15a)

The potential difference between any two points in an electric field is defined as the work done in moving a positive charge of 1 coulomb from one point in the electric field to another.

 

(15b)

Diagram [CHECK THE DIAGRAM BELOW]

 

(15c)

Given: Power p = 1200w, Voltage v = 220v

(i)Resistance, R = v²/p = 220×220/1200 = 40.3ohms

 

(ii)

Energy consumed by one heater = Power × time

= 1200 × 5

= 6000watt-hours

= 6kWh

Energy consumed by 5 heaters = 5 × 6 kWh

= 30kwh

Cost = 30 × 4

= #1,020.00

 

 

Be the first to comment

Leave a Reply

Your email address will not be published.


*