Explanation: Tesla. It is the derived unit of magnetic flux density, which represents the strength of the magnetic field, usually expressed in microtesla (µT). It is equivalent to one weber per meter squared (1 Wb / m2 ).

Explanation: Pyranometer. A type of actinometer (an instrument for measuring ultraviolet radiation). The range of solar radiation extends between 300 and 2800 nm. SI unit of irradiance is W/m2 .

Explanation: The first sextant was produced by John Bird. Thermopile was developed by Leopoldo Nobili and Macedonio Melloni. A pyrometer, invented by Josiah Wedgwood. .

Explanation: Oersted’s Law states that when a steady electric current passes through a wire, it creates a magnetic field around it.

Explanation: wind-direction. Other instruments : Relative humidity – Hygrometer, Temperature – Thermometer, Wind velocity – Anemometer, Rain gauge – Rainfall.

Explanation: Hubble constant. The Faraday constant represents the amount of electric charge carried by one mole, or Avogadro’s number, of electrons. 1 Faraday = F = e × NA ⇒ 9.64853321 × 104 Coulomb per mole. The Planck constant (ML2T -1) and Angular momentum (ML2T -1) have the same dimension.

Explanation: Base quantities (SI Units): Length – Metre, Mass – kilogram (kg), Time – Second (s), Electric current – Ampere (A), Temperature – Kelvin (K), Amount of Substance – Mole (mol), Luminous intensity – Candela (cd).

Explanation: Magnitude. Examples of physical quantities (that can be measured using numbers) are mass, amount of substance, length, time, temperature, electric current, light intensity, force, velocity, density, and many others.

Explanation: Kilowatt hour (KWh). 1 kilowatt hour = 3.6 x 106 joules. Electrical Energy : {SI unit: Joule} The energy derived from the flow of electric charge is called electrical energy.

Explanation: Light-year is the distance a beam of light travels in a single Earth year, or 6 trillion miles. 1 light year = 9.46 × 1015 m and the velocity of light in vacuum = 3 × 108 m/s. Other units of distance are 1 fermi (1 fm) = 10–15 m, 1 angstrom (1 Å) = 10-10 m, 1 astronomical unit (1 AU) = 1.496 × 1011 m, and 1 parsec = 3.08 × 1016 m.

Explanation: Spherometer. A Viscometer (viscosimeter) is an instrument used to measure the viscosity of a fluid. Vernier caliper is used for the measurement of linear dimensions. The Screw gauge measures the diameter or radius or thickness of a thin wire or the thickness of a thin metal sheet with utmost accuracy.

Explanation: In parallel. A voltmeter is an instrument used for measuring the potential difference, or voltage, between two points in an electrical or electronic circuit. They are typically represented by a circle with the letter V inside.

Explanation: It is measured in radians (2π radians in a circle) or degrees (360 degrees to a circle). Solid Angle is measured in steradian.

Explanation: Tera is a unit prefix in the metric system denoting multiplication by one trillion, or 1012 . Hecto means hundred or 102 . Deca means 10. Giga means 109 .

Explanation: Angstrom (Å) is equal to 10-10 metre, or 0.1 nanometre.

Explanation: Linear momentum is dimensionally represented as [M1 L 1 T -1]. Momentum is mass in motion and represented as Mass×Velocity. Impulse is the increase or decrease of an object’s momentum. Therefore, the dimensional formulas of Momentum and impulse are the same. The dimension of stress is [M L -1T -2] and its unit is Pascal; energy is [ML2T -2] and its unit is Joule and the dimension of Work is [ML2T -2] and its unit is Joule.

Explanation: Energy. It is commonly used in atomic and nuclear physics. One electron volt is equal to 1.602 × 10-12 erg, or 1.602 × 10-19 joule. The SI unit of Current is ‘ampere’, Power is ‘watt’ and Potential difference is ‘volt’.

Explanation: Time. The Svedberg unit is a measurement of the sedimentation rate of a particle when it is centrifuged. It is represented by the symbol S. It is actually a measure of time and is defined as exactly 10−13 seconds.

Explanation: volt. Unit and Physical quantities : ‘coulomb’ – Electric charge, ‘ohm’ – Electric Resistance and ‘ampere’ – Electric current.

Explanation: Femto. The other SI prefixes are – Zepto: 10-21 , Atto: 10-18 , Yocto : 10-24 , Pico: 10-12 .

Explanation: The temperature T in degrees Fahrenheit (°F) is equal to the temperature T in degrees Celsius (°C) times 9/5 plus 32. Change in degree fahrenheit = 1.8 ×30 = 54.

Explanation: The SI unit of resistance is ohm. Resistance and conductance are inverse of each other (mho = . 1 / 𝑜ℎ𝑚 )

Explanation: 4.2 joules. 1 calorie is defined as the amount of heat required at 1 standard atmospheric pressure to raise the temperature of 1 gram of water by 1 ° centigrade.

Explanation: 0˚Celsius = 273.15°Kelvin, So 30˚Celsius = (273.15°+ 30˚) Kelvin = 303.15 Kelvin ≅ 303 Kelvin.

Explanation: Fleming’s right and left-hand rule respectively – A right hand and left hand is stretched so that the thumb, middle finger, and index finger form a 90-degree angle with each other. The thumb then represents the direction of motion or force (F), the middle finger the direction of current (I), and the index finger the direction of magnetic field (B).

Explanation: I = mr2 . Where; I = moment of inertia, m = point mass, r = axis of rotation. Moment of inertia – It is a measure of an object’s resistance to changes in its rotation rate. It is a property that depends on both the mass distribution of the object and the axis of rotation. The moment of inertia is analogous to mass in linear motion i.e the larger the moment of inertia, the more torque is required to produce a given angular acceleration. Unit – kg·m², Dimension – [M L2 T 0 ].

Explanation: Dirac Equation : It was formulated by physicist Paul Dirac, it describes the behavior of relativistic electrons in quantum mechanics.

Explanation: Hooke’s law : For small deformations, stress is directly proportional to the strain for many materials. The constant of proportionality is called modulus of elasticity. Stress ∝ strain, Stress = k × strain, where k is the proportionality constant and is known as modulus of elasticity. Hooke’s law is valid only in the linear part of the stress-strain curve. Stress is the restoring force per unit area and strain is the fractional change in dimension.

Explanation: Klystron – Developed by brothers Russell and Sigurd Varian. It is based on the principle of velocity modulation.

Explanation: Momentum of Particles. When a moving charged particle enters a magnetic field then the path followed by the charged particle is circular if the magnetic field is perpendicular to the velocity of the particle. More the radius of the path followed by the particle, the lesser will be the curvature, and the lesser the radius, the more will be curvature. The radius of the circular path in the magnetic field is given by : r = 𝑚𝑣 𝑞𝐵 (where r = radius, m = mass, v = velocity, B = strength of the magnetic field, q = charge on the particle).

Explanation: Magnetic field lines are imaginary lines around the magnet. The magnitude of a field is indicated by its line’s density. Near the South and North Pole of a magnet, the magnetic field is stronger and will get weaker when it moves away from the poles. Properties – They never intersect each other. It takes the least resistant path between the opposite magnetic poles. The length of magnetic field lines will be the same. The magnetic field is a vector quantity because it has both magnitude and direction.

Explanation: P=U/C. Radiation pressure – The mechanical pressure that is applied on any surface due to the exchange of momentum between the electromagnetic field and the object.

Explanation: A solar cell (photovoltaic cell) is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect. Radio is the technology of signaling and communicating using radio waves (frequency between 3 Hz and 3,000 GHz).

Explanation: Expands, contracts. Heating air causes the air molecules to gain thermal energy, move faster, and spread out, resulting in the expansion of air and a decrease in air density. Cooling air causes the air molecules to lose thermal energy, slow down, and come closer together, leading to the contraction of air and an increase in air density.

Explanation: A Bose-Einstein condensate (fifth state of matter) is a state of matter in which extremely cold atoms clump together and act as if they were a single atom. Satyendra Nath Bose founded quantum statistics in 1924. There are five states of matter which are solid, liquid, gas, plasma, Bose-Einstein condensate.

Explanation: According to the nebular hypothesis, gravity caused gas and dust to turn into larger and more compact clouds. This theory was developed by Immanuel Kant and modified in 1796 by Pierre Laplace. Theories : Georges Lemaitre proposed the Big Bang Theory, 1931. Steady State Theory (1948) by Hermann Bondi, Thomas Gold, and Sir Fred Hoyle.

Explanation: 1.5V.

Explanation: The gnomon is the part of a sundial that casts the shadow, and it is probably also the world’s oldest astronomical instrument. Bolometer, instrument for measuring radiation by means of the rise in temperature of a blackened metal strip in one of the arms of a resistance bridge.

Explanation: Humidity. Evaporation – Process by which a liquid is transformed into vapour. Humidity – Concentration of water vapour present in the air. Ambient temperature – Air temperature of any object or environment where equipment is stored. Wind Gradient – Rate of increase of wind strength with unit increase in height above ground level.

Explanation: Tonometer. Viscometer is used to measure the viscosity of fluids. An odometer is an instrument used to measure the distance traveled by a vehicle like a bicycle or a car. A Machmeter is a flight instrument that gives a ratio of airspeed and speed of sound.

Explanation: Ringing of the alarm clock. Quantum mechanics deals with the behavior of matter and light on a subatomic and atomic level. Examples – lasers, electron microscopes, magnetic resonance imaging (MRI) devices and the components used in computing hardware.

Explanation: Lead-acid cell. It is a type of rechargeable battery first invented in 1859 by French physicist Gaston Plante.

Explanation: Magnetostatic. Millikan’s oil drop experiment measured the charge of an electron. Electrically charged oil droplets entered the electric field and were balanced between two plates by altering the field.

Explanation: Maxwell’s. Maxwell first used the equations to propose that light is an electromagnetic phenomenon. Newton’s equation is related to kinematics and motion Einstein’s equation is related to the Theory of relativity. Bohr’s equation is related to atomic physics.

Explanation: Hydrogen being the simplest element is the most abundant element in the universe.

Explanation: Light-emitting Diode (LED) – A semiconductor device, which can emit light when an electric current passes through it. Working principle – Electroluminescence.

Explanation: Refraction. When light moves from rarer (air) to a denser medium (water), it bends towards the normal and if it moves from a denser to a rarer medium, it bends away from the normal.

Explanation: Plane mirror. Lateral inversion is the reversal of a mirror image where the right side of the object appears on the left side behind the mirror. Characteristics of a plane mirror – Image are Virtual and Erect. Image is formed behind the mirror. Size of the image is equal. Distance of image and mirror is equal to the distance of object and mirror.

Explanation: 1/v + 1/u = 1/f. There are two types of spherical mirrors : concave mirrors (If the reflective surface is on the side curved inwards) and convex mirrors (if the reflective surface is curved outwards). The lens formula is 1/v-1/u = 1/f.

Explanation: At infinity – At C – Highly diminished. Spherical mirrors are of two types, concave and convex. Image formation by Concave Mirror (Object Position – Image Position – Image Nature and Size) : (At Infinity – At F – Real, point size); (Beyond Center C – Between C and F (Focus) – Diminished, Real and Inverted); (On Centre – Real, inverted, and same size); (Between Centre (C) and Focus (F) – Beyond Centre – Real, inverted, and larger); (on Focus – Infinity – Real, inverted, and enlarged); (On Focal length (Between Pole and Focus) – Behind Mirror – Virtual, straight and enlarged).