General Knowledge Physics Questions and Answers – Set 2

Correct Answer: C. Graphite

Explanation: In myopia, the eye’s refractive power is too strong, or the eyeball is elongated, causing light rays from distant objects to converge in front of the retina instead of directly on it.

A concave lens is used to correct this condition by diverging the light rays slightly, allowing the image to focus directly on the retina.

Correct Answer: A. Near-sightedness

Explanation:

Myopia (Near-sightedness)

Myopia is a common vision condition where a person can see objects clearly when they are close, but distant objects appear blurry.

Cause:

Myopia occurs when the eyeball is too long or the cornea is too curved. This causes light rays to focus in front of the retina instead of directly on it.

Symptoms:

• Difficulty in seeing distant objects clearly (e.g., reading signs or seeing objects far away).
• Squinting or eye strain.

Correction:

It is corrected using concave (minus power) lenses, which help focus light directly on the retina. Alternatively, refractive surgeries like LASIK can also correct myopia.

This condition contrasts with hypermetropia (far-sightedness), where a person struggles to see nearby objects clearly.

Correct Answer: A. Radiation

Explanation:

The heat from the Sun reaches Earth through radiation

The heat from the Sun reaches Earth through radiation, a process that does not require any medium (like air or water) for the transfer of heat. This is because space is a vacuum, and conduction or convection cannot occur without a medium.

Radiation:

The transfer of energy through electromagnetic waves (such as sunlight). These waves can travel through the vacuum of space and reach Earth.

Conduction:

Heat transfer through direct contact between particles, which cannot occur in a vacuum.

Convection:

Heat transfer through the movement of fluids (liquids or gases), which also requires a medium and does not happen in space.

Reflection:

This refers to the bouncing back of light or heat waves from a surface, which is not how the Sun’s heat is transferred to Earth.

Correct Answer: D. Frequency modulated

Explanation: TV audio signals are transmitted using Frequency Modulation (FM). In FM, the frequency of the carrier wave is varied in accordance with the audio signal, which allows for better sound quality and less interference compared to other methods like Amplitude Modulation (AM). This is why FM is commonly used for TV audio transmission.

Correct Answer: B. Long wavelength

Explanation: Red light has a long wavelength compared to other visible colors. Longer wavelengths of light are less scattered in the air, making red light more visible over long distances, especially in foggy or smoky conditions. This property makes it ideal for use in signals like traffic lights or warning signals..

Correct Answer: A. Johannes Kepler

Explanation:.

Johannes Kepler’s Laws of Planetary Motion

Johannes Kepler formulated the laws of planetary motion. His three laws describe the motion of planets around the Sun:

Kepler’s First Law:

Planets move in elliptical orbits with the Sun at one focus.

Kepler’s Second Law:

A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.

Kepler’s Third Law:

The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.

These laws laid the groundwork for later developments in astronomy and were crucial for Isaac Newton’s work on gravity.

Correct Answer: D. Magnified, virtual, and inverted image

Explanation: In pathology, compound microscopes are commonly used, which produce magnified images of the specimen. The image formed is virtual (it cannot be projected onto a screen) and inverted (upside down). This is due to the way light passes through the lenses, where the objective lens magnifies the image, and the eyepiece lens then further magnifies and inverts it..

Correct Answer: C. Hot and dry climate

Explanation: Air coolers work best in hot and dry climates because they rely on the process of evaporative cooling. In such environments, water evaporates quickly, absorbing heat and cooling the air. In humid conditions, the air already contains a lot of moisture, which reduces the efficiency of air coolers. Therefore, air coolers are less effective in humid or damp climates.

Correct Answer: C. Electrons

Explanation: In a metal wire, electric current is caused by the movement of electrons. Metals have free electrons that are not tightly bound to atoms, allowing them to move easily when a potential difference (voltage) is applied across the wire. These free electrons flow from the negative end to the positive end, creating an electric current.

Correct Answer: B. Sphere

The rate of cooling of an object is influenced by its surface area and volume. The sphere has the smallest surface area to volume ratio compared to the cube and the circular plate. According to Newton’s Law of Cooling, the larger the surface area in relation to the volume, the faster the rate of heat loss. Since the sphere has a lower surface area relative to its volume, it will lose heat more slowly than the other shapes (cube and circular plate) with higher surface area-to-volume ratios.