Waec Physics 1999 Past Questions and Answers

Question 36:

• WAEC 1999

Magnetic flux density is defined as the

A. Total number of magnetic lines of force surrounding a magnet
B. Number of magnetic lines of force per unit area normal to the magnetic field
C. Strength of the magnetic field surrounding a current-carrying conductor
D. Magnetic force exerted on a unit magnetic pole

Question 37:

• WAEC 1999

The voltage and current in the primary of a transformer are 200V and 2Arespectively. lf the transformer is used to light ten 12 V, 30 W bulbs, calculate its efficiency.

A. 100%
B. 90%
C. 75%
D. 50%

Question 38:

• WAEC 1999

In a uniform electric field, the magnitude of the force on a charge of 0.2 C is 4N. Calculate the electric field intensity

A. 20 N C^-1
B. 8 N C^-1
C. 5 N C^-1
D. 2 N C^-1

Question 39:

• WAEC 1999

A 10- Ω coil takes 21 s to melt 10g of ice at 0^oC. Assuming no heat losses, determine the current in the coil. (Specific latent heat of fusion of ice = 336 Jg^-1)

A. 16A
B. 5A
C. 4A
D. 3A

Question 40:

• WAEC 1999

A point charge of magnitude 2μC is moved through a distance of 0.02 m against uniform field of intensity 25 Vm^-1 Calculate the work done on the charge

A. 5.0 x 10⁶J
B. 1.0 x10^-6J
C. 5.0 x10^-7J
D. 1.0 x 10^-2J