Physics MCQs

Notes:
Myopia (short-sightedness) occurs when images are focused in front of the retina, causing distant objects to appear blurry. It is commonly due to an elongated eyeball or excessive corneal curvature. This defect is corrected using concave (diverging) lenses. Hyperopia, by contrast, focuses images behind the retina.

Notes:
A refrigerator is like a heat engine. It extracts heat from low temperature reservoir and transfer it to high temperature. If a refrigerator’s door is kept open, then room will become hot, because then refrigerator exhaust more heat into the room than earlier.

Notes:
The mean value of the acceleration due to gravity (often denoted as “g”) at Earth’s surface is approximately 9.81 meters per second squared (m/s²). This value represents the average gravitational acceleration experienced by objects on the surface of the Earth. It is important to note that this value is not constant everywhere on Earth’s surface and can vary slightly due to factors such as location, altitude, and the density of the Earth’s crust.

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Bats use SONAR (Sound Navigation & Ranging).Sonar is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.

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A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. A cyclotron accelerates charged particles outwards from the center along a spiral path.

Notes:
The north pole of a magnet in a compass points north because it is attracted to the Earth’s magnetic south pole, which is located near Earth’s geographic north pole. The geographic north pole of earth corresponds to magnetic south pole and geographic south pole of earth corresponds to magnetic north pole. The direction in which a compass needle points is known as magnetic north. This is not exactly the direction of the North Magnetic Pole. Instead, the compass aligns itself to the local geomagnetic field, which varies in a complex manner over the Earth’s surface. The angular difference between magnetic north and true north (defined in reference to the Geographic North Pole), at any particular location on the Earth’s surface, is called the magnetic declination. Most map coordinate systems are based on true north, and magnetic declination is often shown on map legends so that the direction of true north can be determined from north as indicated by a compass.

Notes:
Quartz crystals have piezoelectric properties: they develop an electric potential upon the application of mechanical stress. An early use of this property of quartz crystals was in phonograph pickups. A common piezoelectric use of quartz today is as a crystal oscillator. The quartz clock is a familiar device using the mineral. Quartz is also strongly pyroelectric. Temperature changes create positive and negative charges within the crystal.

Notes:
The north pole of a magnet in a compass points north because it is attracted to the Earth’s magnetic south pole, which is located near Earth’s geographic north pole. The geographic north pole of earth corresponds to magnetic south pole and geographic south pole of earth corresponds to magnetic north pole. The direction in which a compass needle points is known as magnetic north. This is not exactly the direction of the North Magnetic Pole. Instead, the compass aligns itself to the local geomagnetic field, which varies in a complex manner over the Earth’s surface. The angular difference between magnetic north and true north (defined in reference to the Geographic North Pole), at any particular location on the Earth’s surface, is called the magnetic declination. Most map coordinate systems are based on true north, and magnetic declination is often shown on map legends so that the direction of true north can be determined from north as indicated by a compass.

Notes:
In the presented choices, the Fermi stands as the smallest unit of length measurement. It is equal to 10^-15 m. Comparatively, 1 Micron equals 10^-6 m, 1 Nanometer equals 10^-9 m, and 1 Angstrom equivalent to 10^-10 m. All these units are commonly used to measure minuscule distances, particularly in the realm of nanotechnology and particle physics. However, the Fermi, named after the esteemed physicist Enrico Fermi, remains the smallest.

Notes:
Vectors addition is associative and commutative. But vectors of the same nature alone can be added. Example: a Force vector cannot be added to velocity vector as they are of different nature.