A rectangular glass prism of thickness d and absolute refractive index n is placed on a point object which is viewed vertically downward from above the prism. Which of the following expressions correctly defines the apparent upward displacement of the object?

• A. \(\frac{d}{n}\)
• B. dn
• C. \(\frac{d}{n - 2}\)
• D. \(\frac{d(n - 1)}{n}\)

A force of 500N is applied to a steel wire of cross-sectional area 0.2m², The tensile stress is

• A. 2.5x10⁴Nm^-2
• B. 1.0x10²Nm^-2
• C. 1.0x10³Nm^-2
• D. 2.5x10³Nm^-2

In the diagram below, a 200 W bulb is lighted by a 240 V a.c mains supply. If 1kwh is sold at ₦40, the cost of keeping the bulb lighted for a day is

• A) ₦1,920.00
• B) ₦192.00
• C) ₦19.20
• D) ₦1.92

The diagram below shows a meter bridge in which two of thee arms contain resistances R and 2Ω. A balance point is obtained at 60cm from the left end , calculate the value of R

• A. 1.2Ω
• B. 1.3Ω
• C. 3.0Ω
• D. 6.0Ω

Which of the following statements are correct about an object in equilibrium under parallel forces? i. the total clockwise moments of the forces about any point equals the total anti-clockwise moments about the same point. ii. the total forces in one direction equals the total forces in the opposite direction. iii. the resolved components along the x-axis equals the resolved components along the y-axis.

• A. i and ii only
• B. i and iii only
• C. ii and iii
• D. i, ii, and iii only

The maximum density of water occurs at a temperature of

• A. 0°C
• B. 4°C
• C. 37°C
• D. 273°C

The efficiency of the pulley system shown below is 80%. find the effort E required to lift the load of 1200N

• A) 275N
• B) 325N
• C) 375N
• D) 573N

A block and tackle pulley arrangement has 6 pulleys in which an effort of 50N supports a load of 200N, calculate the efficiency of the machine

• A. 80.0%
• B. 76.6%
• C. 66.7%
• D. 60.7%

Which of the following objects is not a conductor of electricity?

• A. The Earth
• B. Human body
• C. Iron rod
• D. Dry wood

Shadows and eclipses result from the

• A. refraction of light
• B. reflection of light
• C. defraction of light
• D. rectilinear propagation of light