Explanation

• In longitudinal waves, particles of the medium vibrate parallel to the direction of wave propagation.
• These waves consist of compressions and rarefactions.
• Sound waves in air are a common example of longitudinal waves.

Last verified on 31-10-2026

Explanation

Given:

Object distance (u) = 30 cm

Focal length (f) = 15 cm

2 x f = 2 x 15 = 30 cm

So object is at 2F.

Lens formula:

1/f = 1/v + 1/u

1/15 = 1/v + 1/30

1/v = 1/15 - 1/30

1/v = 1/30

v = 30 cm

Image also forms at 30 cm on other side.

Magnification = v / u = 30 / 30 = 1

Magnification 1 means image size = object size.

Answer: The same - inverted and same size.

Last verified on 31-10-2026

Explanation

• Blue light has the shortest wavelength.
• In the visible spectrum, wavelength decreases from red to violet.

Additional information:

• Red light rays have the lowest frequency and highest wavelength value.

Last verified on 10-06-2026

Explanation

• Drag force opposes an object's motion through a fluid, such as air or water.
• Drag force generally increases as the object's speed increases.
• At ordinary speeds, drag is often proportional to speed; at higher speeds, it is commonly proportional to the square of speed.

Last verified on 31-10-2026

Explanation

• Newton’s Second Law states that the net force equals mass multiplied by acceleration.
• Acceleration can be calculated by dividing the net force by the object's mass.
• The SI unit of acceleration is metres per second squared (m/s²).

Last verified on 31-10-2026