2014 WAEC PHYSICS ESSAY AND OBJECTIVES SOLUTUONS

VERIFIED PHYSICS OBJ
1D,A,B,A,B,A,C,B,B,B
11D,C,A,B,C,B,B,A,A,C
21A,B,B,C,C,D,C,D,B,B
31C,B,D,C,B,C,D,D,A,A
41D,D,B,A,D,B,D,A,A,B
7a)
The minimum energy of the incident ray of the light must be equal to the work function of the material or above the work function of the metal.
(7b)(i) polarization.
(ii) diffraction.
(9)(a)
Heat capacity is the quantity of heat required to change the temperature of a substance by 1 k or 1degree Celsius
(9b) I. It changes the phase
(9d) Given,
mass of pepper soup, m=800g
=0.800kg
Initial temprature of pepper soup,
tita =30degree C
Power of the microwave oven,
P=1200w
Time taken, t =3minutes =3*60s =180s.
Specific heat capacity of pepper soup,
c=4000j/kg k.
9di)final temperature of the pepper soup,
@2=? ,
Heat given by d microwave oven= Heat absorbed by d pepper soup.
Pt= mc(@2 – @1),
1200 * 180= 0.8 * 4000(@2 – 30),
216000= 3200(@2 – 30),
@2 – 30=67.5 ,
@2 = (67.5 + 30)degrees ,
@2 = 97.5degree Celsius
NOTE THAT: @ Means tita sign
5a)Gas can conduct electricity under low pressure and high votage.
5b)cathode
2. R=(U^2sin2@)/g
78=(30*30 sin2@)/10
0.8667=sin2@
2@=60
@=30
4) young modulus=stress/strain
stress=F/A=35000/4=8750
strain=e/l=0.025/50=0.0005
young modulus=8750/0.0005=17500000
(9Dii) containers with tight-fitting lids are not suitable for use in microwave cooking because there must be room for expansion which can only be catered for if the lids are not tight-fitted
(9diii) there is dent on the container because the final temperature was so large compared to the material used in making the container,I.e plastic.and plastics are not very good for such heat.The cooling of the plastic cannot be uniform.
(8a)
(i) Rotational Motion
I.The movement of the blades of a fan.
II.The motion of the wheel of a car.
(ii) Linear Motion
I.The motion of a boy from a point to another point on a straight line.
II.The motion of a ball on a straight course.
11a.EMF is the potential difference between the terminals of a cell when it is not delivering any current in an external circuit
11bi)when a steady current flows along a uniform wire, there is steady potential drop throughout its length. thus each unit length of the wire will have a constant P.D. across it
ii)-the potentiometer measures EMF correctly since no correction is needed to be made for the volt lost
-it measures the EMF to a higher degree of