Question 781:

• JAMB 1994

A pipe of length 45cm is closed at the end. Calculate the fundamental frequency of the sound wave generated in the pipe if the velocity of sound in air is 360ms^-1 [Neglect end correction]

A. 5.5Hz
B. 148.5Hz
C. 200.0Hz
D. 550.0Hz

Question 782:

• JAMB 1994

The note produced by a stretched string has a fundamental frequency of 400Hz. If the length of the string is doubled while the tension in the string is increased by a factor of 4, the frequency is

A. 200Hz
B. 400Hz
C. 800Hz
D. 1600Hz

Question 783:

• JAMB 1994

To produce a parallel beam of light from a concave mirror, the distance at a which the lamp should be placed from the mirror is equal to

A. The focal length
B. Two times the focal length
C. The distance of the image
D. Two times the radius of curvature

Question 784:

• JAMB 1994

Light of frequency 6.0 x 10¹⁴ Hz travelling in air is transmitted through glass or refractive index 1.5. Calculate the frequency of the light in the glass

A. 4.0 x 10¹⁴Hz
B. 6.0 x 10¹⁴Hz
C. 7.5 x 10¹⁴Hz
D. 9.0 x 10¹⁴Hz

Question 785:

• JAMB 1994

An object is placed in front of a converging lens of a focal length 20cm. The image is virtual and has a magnification of 2. What is the distance of the object from the lens?

A. 5cm
B. 10cm
C. 30cm
D. 40cm