# User Forum

Subject :NSO    Class : Class 8

A student sets up a slinky PQ on a smooth table top in the manner as shown in figure. How can he produce transverse waves in the slinky by moving its free end Q?

A At an angle of 45° with the table top
B Backward and forward along the length of the slinky
C Up and down
D Left and right

## Ans 1:

Class : Class 9

Class : Class 1

In transverse wave, vibration of a wave is perpendicular to its direction of propagation of wave.

Class : Class 8

## Ans 4:

Class : Class 8
Won't moving the slinky up and down produce the same result? You can check b observing from the side.

Class : Class 9

## Ans 6:

Class : Class 9
The correct answer is D. In a transverse wave the direction of the movement of the particle is perpendicular to direction of motion of the wave. So, over here, when we move the end Q from left and right , it will produce a transverse wave,. You can check it by observing it from the top.

## Ans 7:

Class : Class 8
In my opinion, the answer should be both option (C) and option (D). Transverse waves are waves in which the motion of particles are perpendicular to the motion of the wave (for example, light). Moving the slinky at an angle of 45 degrees to the table would create a wave, just not a perpendicular one, and thus not a transverse wave. This excludes option (A). Option (B) is also excluded, as it creates a longitudinal wave (motion of the particles is parallel to the motion of the wave). Option (C) involves the wave being moved up and down (assumed to be at right angles, since it is not mentioned). The slinky thus also moves up and down, and creates a transversal wave (as the motion of the wave is from Q to P, and the motion of the parts of the slinky is perpendicular to line QP). Option (C) is thus correct. Option (D) involves the wave being moved left to right (assumed to be at right angles, since it is not mentioned). This also created a transverse wave (as the motion of the parts of the slinky is perpendicular to the motion of the wave from Q to P). Option (D) is thus, also correct. Since we live in a three dimensional world, and it is not mentioned in the question that the experiment is performed in a 2 dimensional world, we can assume that the experiment is done in a 3D world. Due to the presence of length, breadth and height, the slinky can be moved in two ways perpendicular to line QP (i.e. the slinky). Given that both ways this can be done are mentioned in the question, both options must be correct. Therefore, I opine that the correct answer is both option (C) and option (D).

Class : Class 9

Class : Class 7

Class : Class 8