Question 91:

• JAMB 1979

It is known that a neutron exists in a light atomic nucleus. Which of the following also exists in the nucleus?

A. An electron
B. A \(\beta\)-particle
C. An \(\alpha\)-particle
D. A proton
E. An atom

Question 92:

• JAMB 1979

A weight of 1000 grams hangs from a lever 20cm to the fulcrum. At the left is a 500-gram weight 20cm from the fulcrum, and a 200-gram weight x cm away from the fulcrum. What is the value of x that will make the lever balanced?

A. 50cm
B. 20cm
C. 10cm
D. 30cm
E. 70cm

Question 93:

• JAMB 1979

Radio carrier waves are generated by causing electrons to oscillate rapidly in

A. A microphone
B. A television camera
C. An antenna
D. Coaxial cables
E. A transmitter

Question 94:

• JAMB 1979

Which of the following statements is correct? Silvered walls of a vacuum flask are used to prevent

A. Heat loss due to conduction
B. Vacuum loss
C. Heat entry into the inner flask due to convection
D. Heat loss due to radiation
E. Heat loss due to convection

Question 95:

• JAMB 1979

A concave lens of focal length 20cm form an image 1/2 the size of the object. The object distance is

A. 100cm
B. \( \frac{100}{q} \)
C. 60cm
D. \( \frac{60}{7} \)
E. None of the above