Explanation

• Red light has the longest wavelength, approximately 620-750 nanometers (nm).
• While violet light has the shortest wavelength, approximately 380-450 nm.
• The order of colours in the spectrum, from longest to shortest wavelength, is: Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV).

Explanation

Time period T = 1/frequency 1/0.5 = 2 seconds.

The time period is the time taken for one complete oscillation.

Explanation

According to the law of reflection, angle of incidence = angle of reflection.

So, if light strikes at 30°, it reflects at 30°.

Explanation

Power = 1/f (in meters)

f = 8 cm = 0.08 m

Power = 1/0.08 = 12.5 D

Explanation

If the original cable breaks at a stretch of 2 mm, each half will have half the length and thus half the maximum stretch:

Maximum stretch for half = 2 mm / 2 = 1 mm.

Explanation

Waves produced by oscillation of material particles require a medium to travel, called mechanical waves.

Examples include sound waves and water waves.

Explanation

KE = 1/2mv²

Given m = 0.03 kg, v = 400 m/s

KE = 1/2 × 0.03 × 400 × 400

= 1/2 × 0.03 × 160000

= 1/2 × 4800

= 2400 J

Explanation

The turns ratio of a transformer is given by:

n = N₂ / N₁ = V₂ / V₁

Where:

- n is the turns ratio

- N₁ and N₂ are the number of turns in the primary and secondary coils

- V₁ and V₂ are the primary and secondary voltages

Given n = 5:

V₂ / V₁ = 5

This means the secondary voltage is greater than the primary voltage by a factor of 5.

Explanation

After 3 half-lives, the mass remaining is calculated as:

Mass remaining = Initial mass / 2³

= 160 μg / 8

= 20 μg

Explanation

The direction of the induced emf is predicted by Lenz's Law.

It states that the induced emf always acts to oppose the change causing it.