2021 WAEC Physics Objective Essay Question And Answer

2021 WAEC Physics Objective Essay Question And Answer

WAEC Physics questions and answers Objective answer 1-10: DACAACBBCC 11-20: BDBABBACAC 21-30: BCBACBBACA 31-40: BDDDDACCCA 41-50: AAAABBCBBC Essay answers (1) Original length Lo= 3m Extension e = 310 = 3*3= 9m F×e F=ke where k = 982.3NM-² F=982.3*9=8,840.7N The five that produce the extension F = 8.840.7N (2a) Flat metal plate are mainly used to collect heat for space heating in solar panels for heat transfer. (2b) Thermal insulator is used for reduction of heat transfer between objects in thermal contact (2c) tubes is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. (3a) highly purified silica glass. (3b) To confine the optical signal in the core the refractive index of the core must be greater than that of the cladding. (5) Escape velocity = VE Radius of the earth = R Acceleration due to gravity = 10ms² Escape velocity BE=√2R VE=√2*10R VE=√20R (6) Angle at horizontal θ = 30° Time of light , T = 25sec Velocity of projection u = ? But T=2using sinθ/g 25= 2u*sin30/10 25=0.5u/5 0.5u=125 U=125/0.5 =250ms-¹ (7) (i)coherence (ii)directionality (iii)monochromatic (8ai) A torque is defined as a measure of the force that can cause an object to rotate about an axis WAEC Physics Questions 2021 and Answers (8aii) Factors that determine torque are; – The magnitude of the force – The radius – The angle between the force and the lever arm (8bi) Free fall simply means the act of which are objects fall freely under the influence of gravitational force. An object under free fall does not encounter air resistance (8bii) Height of tower H = 40.0m Velocity v = 10.0m/s, time t= ? , g=10.0m/s Using the relation S= ut + 1/2gt^2 H= ut + 1/2gt^2 40= 10t + 1/2*10t^2 4= t + t^2/2 = t^2 + 2t – 8=0 ( solving quadratically) = (t+4)(t-2)=0 t+4=0 or t-2=0 t= -4 or t=2 Therefore time to fall on the ground t=2s (8c) R.d of oil =R1 = 0.72 R.d of water = R2=1.00 R.d of liquid= R1/R2= 0.72/1 = 0.72 R.d = density of wood(p1)/density of water(p2) 0.72=P1/1.00 P1= 0.72*1.00=0.72g/cm³ But density of wood= mass of wood/volume of wood 0.72= mass of wood/8*8*8 Mass of wood = 0.72*512 = 368.64g Bookmark this page and keep refreshing for more updates as they unfold. Subscribe to our notifications and drop your email when prompted for fresh updates.