Explanation

• Atoms are classified based on atomic number and mass number.
• When atoms of different elements have the same mass number, they are called isobars.
• Mass number = protons + neutrons.
• Isobars have different atomic numbers but equal mass numbers.
• They are not chemically identical elements.

Last verified on 08-05-2026

Explanation

• Radioactive emissions include alpha, beta, and gamma rays.
• Charged particles are deflected in electric and magnetic fields.
• Neutral radiation does not show deflection.
• Gamma rays are electromagnetic waves with no charge.
• Therefore, they pass straight without deviation.

Last verified on 08-05-2026

Explanation

• Photon energy depends on the frequency of light.
• Higher frequency means higher energy.
• This relation was explained by Max Planck.
• Photon is a tiny packet of light energy.

Last verified on 07-05-2026

Explanation

• In the photoelectric effect, light ejects electrons from a metal surface.
• Increasing light intensity increases the number of photons hitting the surface.
• More photons release more electrons.
• The photoelectric effect supported the quantum theory of light.
• Albert Einstein received the Nobel Prize for explaining this effect.

Last verified on 07-05-2026

Explanation

• Neap tides occur when the Sun and Moon pull Earth’s water from different directions.
• This happens when the Moon is at a right angle (90°) to the Earth-Sun line.
• During neap tides, the difference between high and low tide is small.
• Neap tides occur twice every lunar month.
• Spring tides happen during full moon and new moon phases.

Last verified on 07-05-2026

Explanation

• Laser light is monochromatic, meaning it has one color.
• It contains only one wavelength and one frequency.
• This makes laser light very pure and focused.
• They are used in surgery, barcode scanners, and fiber optics communication.

Additional information:

• Polychromatic (white light) → Multiple wavelengths

Last verified on 07-05-2026

Explanation

• Alpha, Beta, Gamma, and X-rays are types of radiation.
• In an electric field, charged particles are deflected.
• Beta radiation is light and carries a negative charge, so it bends the most.

Additional information:

Deflection in Electric Field (Comparison)

• Alpha (α) rays → Less deflected (heavy mass + positive charge)
• Gamma (γ) rays → No deflection (no charge)
• X-rays → No deflection (neutral electromagnetic waves)

Last verified on 07-05-2026

Explanation

• Quantum theory states that energy levels in atoms are discrete (fixed and separate).
• Electrons can only exist in specific energy levels, not in between.
• They absorb or emit energy when moving from one level to another.

Last verified on 06-05-2026

Explanation

• In the photoelectric effect, electrons are emitted only if light has a minimum required frequency (threshold frequency).
• Increasing intensity alone cannot eject electrons if frequency is too low.
• Thus, frequency of light is the key factor.

Last verified on 06-05-2026

Explanation

• High tides occur when the gravitational pull of the Moon and Sun align.
• This happens during new moon and full moon phases.
• Their combined force produces stronger tides (spring tides).

Last verified on 06-05-2026