Question 121:

• JAMB 1980

Which of the following statements on the use of X-rays is incorrect? X-rays are used

A. In hospitals to obtain photogaphs of tissues and bones in the body
B. For the treatment of malignant growths like cancer cells
C. In detecting fingerprints
D. To reveal hidden flaws in metal castings and welded joints
E. To detect alternations which have been made to works of art

Question 122:

• JAMB 1980

What is the relative permitivity of a capacitor if its capacitance with a medium as dielectric is 16 farads and its capacitance with vacuum as dielectric is 2 farads?

A. O
B. \(\frac{1}{2}\)
C. 2
D. 8
E. 32

Question 123:

• JAMB 1980

If the magnification of a virtual image formed of an object 10cm from a convex lens is 3, then the focal length of the lens is

A. 10cm
B. 15cm
C. 16cm
D. 19cm
E. 20cm

Question 124:

• JAMB 1980

A quantity of sungas at -133^{[/sup] occupies 1/3m[sup]3} under pressure 1.4 x 10⁵ Nm^-2. if the gas occupies 31 m^-2 at 37^oC, its pressure will be

A. 1.26 x 10³Nm^-2
B. 3.3 x10⁴Nm^-2
C. 1.35 x 10⁴Nm^-2
D. 2.2 x 10⁴Nm^-2
E. 10⁵Nm^-2

Question 125:

• JAMB 1980

A stand-by generator is connected to fifteen 40 W lamps and musician's 600 W amplifying system. How much energy is used if the generator runs for 6 hours?

A. 3.84k Wh
B. 7.20k Wh
C. 8.40k Wh
D. 12.00k Wh
E. 14.56k Wh