Physics

Velocity is defined as displacement per unit time. Displacement has the dimension of length (L), and time has the dimension (T). Therefore, the dimension of velocity is length divided by time, which is LT^-1.

A radian is a unit of angular measure, not length. Light year, angstrom, and micron are all units used to measure length or distance.

The resultant of two vectors with magnitudes 10N and 15N can range from the difference (15N - 10N = 5N) to the sum (15N + 10N = 25N). Therefore, 30N is not possible as a resultant magnitude.

Antimatter is composed of antiparticles corresponding to all types of particles, including anti-electrons (positrons), anti-protons, and anti-neutrons. Therefore, all the options listed are components of antimatter.

Speed is a scalar quantity because it has only magnitude and no direction, unlike displacement, velocity, and acceleration which are vector quantities having both magnitude and direction.

Mach number is defined as the ratio of the speed of an object to the speed of sound in the surrounding medium. Therefore, it measures speed relative to the speed of sound.

When two vectors are antiparallel, they point in exactly opposite directions. The resultant vector is found by subtracting the smaller vector from the larger one, which corresponds to a - b if a and b are the vectors.

Both alternating current (A.C.) and direct current (D.C.) produce the same heating effect when passing through a resistance, as the heating depends on the power dissipated (I²R), which is similar for equal RMS currents.

An electric motor can be used as a dynamo (generator) because both devices operate on the principle of electromagnetic induction; when an electric motor is driven mechanically, it generates electricity, functioning as a dynamo.

Conductance (G) is the reciprocal of resistance (R). Given R = 0.5 ohm, G = 1 / 0.5 = 2 siemens (S).

The SI unit of acceleration is meters per second squared (m/s²), which represents the change in velocity per unit time. Option B correctly states this unit.

A parabolic velocity-time graph indicates that the velocity changes with time in a quadratic manner, which means the acceleration is not constant but varies with time. The acceleration is the slope of the velocity-time graph, so a curved (parabolic) velocity-time graph corresponds to variable acceleration. Constant acceleration produces a straight line velocity-time graph (linear velocity change). Therefore, if the velocity-time graph is parabolic, the body possesses variable acceleration.

The field particle of electromagnetic interaction is the photon, which is the quantum of the electromagnetic field and mediates electromagnetic forces.

A unit vector has a magnitude of one and is used specifically to indicate the direction of a vector without regard to its magnitude.

The area under a velocity-time graph represents displacement because it is the integral of velocity with respect to time, which gives the change in position.

The Mohs scale is a scale of mineral hardness used to measure the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. Therefore, it is used to measure hardness.

In a stationary (standing) wave, nodes are points of zero displacement and antinodes are points of maximum displacement. The distance between two consecutive nodes or two consecutive antinodes is half the wavelength (λ/2). The distance between a node and the adjacent antinode is λ/4. Since the question asks for the distance between any two consecutive nodes or antinodes, the correct answer is λ/2, which corresponds to option B.

The international prototype kilogram, historically kept near Paris, is a platinum-iridium cylinder with a mass of exactly 1 kilogram. This standard was used to define the kilogram until the redefinition based on physical constants.

Due to relative motion between an observer and a frame of reference, time intervals measured in the moving frame appear longer (dilated) to the observer. This phenomenon is known as time dilation in special relativity.

A vector with magnitude one is defined as a unit vector. It is used to indicate direction without affecting magnitude.

A shunt is a low resistance path that allows current to bypass a part of a circuit, commonly used to divert current around a component.

The SI unit of heat is the joule (J), which is the standard unit of energy in the International System of Units. Heat is a form of energy transfer, so it shares the same unit as energy.

The visible spectrum of light ranges approximately from 3900 to 7600 angstroms, which corresponds to wavelengths visible to the human eye. This range covers violet to red light.

The power of a lens (P) in diopters is defined as the reciprocal of its focal length (f) in meters, i.e., P = 1/f. Therefore, if the power is 1 diopter, the focal length must be 1 meter.

Kinetic energy (KE) is given by KE = p^2/(2m), where p is momentum. If momentum is doubled, KE increases by a factor of 2^2 = 4, so kinetic energy becomes four times the original.