Explanation

The direction of induced e.m.f. (electromotive force) in a circuit is determined by Lenz's law.

It states that the induced e.m.f. will oppose the change in magnetic flux that induced it.

This is a consequence of the conservation of energy.

Explanation

Magnetic poles always exist in pairs, with every magnet having a north pole and a south pole.

Like poles (north-north or south-south) repel each other.

Unlike poles (north-south or south-north) attract each other.

Explanation

Electromagnetic waves are typically listed in order of increasing wavelength (or decreasing frequency) as follows:

• Gamma-rays (shortest wavelength, highest frequency)
• X-rays
• Microwaves (longer wavelength, lower frequency)

Explanation

Sound is a form of mechanical energy that is produced by vibrations or oscillations of particles in a medium, such as air, water, or solids.

When an object vibrates, it creates a disturbance in the medium around it, causing the particles to oscillate back and forth.

This oscillation, or wave motion, is what we perceive as sound.

Explanation

Ohm's law is not applicable to Semiconductors, as the relationship between voltage and current does not remain constant in these devices.

Semiconductors have a non-linear current-voltage characteristic, making Ohm's law inapplicable.

Explanation

When two capacitors of equal capacitance (C) are connected in series, the equivalent capacitance (Ceq) is half the value of one capacitor:

Ceq = (C × C) / (C + C) = (C × C) / 2C = C/2

In this case, C = 8 µF, so:

Ceq = 8 µF / 2 = 4 µF

Therefore, the equivalent capacitance of the two 8 µF capacitors connected in series is 4 µF.

Explanation

Sound travels faster in solids than in gases because the molecules in a solid are packed more tightly together, allowing the energy to be transferred more efficiently.

In contrast, in a gas, the molecules are spaced farther apart and are free to move randomly, making it harder for the sound wave to propagate.

Explanation

• A magnifying glass, also known as a convex lens.
• It forms an enlarged virtual image that is upright.

The image formed by a magnifying glass:

• Image type: Virtual
• Orientation: Upright
• Size: Enlarged