Physics 1990 Jamb Past Questions and Answers

Question 26 :

• JAMB 1990

In a resonance tube experiment, the effective length of the air column for the first resonance is 20cm when set into vibration by a tuning fork of frequency 480Hz. Neglecting and effect, the velocity of sound in air is

A. 96ms^-1
B. 255ms^-1
C. 340ms^-1
D. 384ms^-1

Question 27 :

• JAMB 1990

An organic pipe closed at one end is 80cm long. Determine the frequency of the fundamental note assuming that the speed of sound in air is 340ms-1

A. 106Hz
B. 213Hz
C. 318Hz
D. 425Hz

Question 28 :

• JAMB 1990

A sonometer wire of length 100cm under a tension of 10N, has a frequency of 250Hz. Keeping the length of the wire constant, the tension is adjusted to produce a new frequency of 350Hz. The new tension is

A. 5.1N
B. 7.1N
C. 14.0N
D. 19.6N

Question 29 :

• JAMB 1990

One of the properties of the earth's magnetic field is that the

A. North pole lies in the northern hemisphere
B. Geographic and magnetic meridians coincide
C. Earth's magnetic flux is entirely horizontal at a place where the magnetic dip is zero
D. Earth's magnetic flux is entirely vertical at a place where the magnetic dip is zero

Question 30 :

• JAMB 1990

Which of the following statements are true of an insulated charged body carrying positive charge? i. it contains excess positive charges. ii. it creates an electric field. iii. it possesses potential energy. iv. it carries electric current.

A. I and iv only
B. I and ii only
C. I, ii, iii only
D. I, ii, iii and iv