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.

Explanation

Speed of sound in air is proportional to the square root of absolute temperature v ∝ √T.

To double the speed, temperature must increase 4 times in Kelvin:

At 27°C = 300 K → 4 × 300 = 1200 K → 1200 - 273 = 927°C

Explanation

For projectile motion, two complementary angles θ and 90° - θ give the same range if the initial velocity is constant.

Since 10° + 80° = 90°, the angles 10° and 80° are complementary and will have equal ranges.

Explanation

Absolute alcohol refers to 100% pure ethanol, free from any water content.

It is used in laboratories and industrial applications where water-free alcohol is essential.

Explanation

Pinworms (Enterobius vermicularis) are roundworms that cause infections in the human intestines.

They are common in children.

It spread through contaminated surfaces or hands.

Explanation

Given lim x → 1⁺ (2 + √x - 1)

As x approaches 1 from the right:

√x approaches √1 = 1

So, √x - 1 approaches 1 - 1 = 0

2 + 0 = 2

The limit is 2.

Explanation

ln3 means the natural logarithm of 3 (log base e).

Its approximate value is 1.0986.

Explanation

Pressure P = F/A. The uncertainty in P is given by:

(ΔP/P) = (ΔF/F) + (ΔA/A)

Given ΔF/F = 2% and ΔA/A = 5%,

(ΔP/P) = 2% + 5% = 7%

Explanation

Bronchial respiration refers to respiration through gills, mainly seen in fishes.

Gills extract dissolved oxygen from water and expel carbon dioxide.