Which of the following is NOT a part of a d.c. electric motor?
Field-magnet
Armature
Commutator
Transformer
Correct answer is D
No explanation has been provided for this answer.
The vibration of an air column produces the sound in the
piano
guiter
flute
school handbell
Correct answer is C
No explanation has been provided for this answer.
1 Hz
2 Hz
4 Hz
8 Hz
Correct answer is A
Total distance = 2 x 160 = 320cm
Total time = \(\frac{320}{320}\) = 1s
F = \(\frac{1}{1}\) = \(\frac{1}{1}\)
= 1Hz
Which of the following is true of the loudness of sound? It
depends on the square of the amplitude of the vibrating body
is proportional to the distance of the observer from the source of the sound
is greatest in vacuum
is dependent in vacuum
Correct answer is A
No explanation has been provided for this answer.
1.0cm
1.5cm
2.0cm
5.0cm
Correct answer is A
\(\lambda\) = \(\frac{v}{f}\)
= \(\frac{20}{10}\)
= 2cm ; distance between adjacent nodes
= 2cm \ 2
= 1cm