Physics

Beta particles are high-speed electrons emitted during radioactive decay, which is why option B (Electrons) is correct.

Although the satellite moves at a uniform speed, its direction is continuously changing as it orbits the Earth, which means it is undergoing centripetal acceleration. Therefore, the motion is accelerated, not without acceleration.

A neutron is a neutral particle because it has no electric charge, unlike alpha particles, electrons, and protons which are charged particles.

The coulomb (C) is the SI unit of electric charge, not velocity, temperature, or mass. Therefore, none of the given options A, B, or C are correct, making option D the correct choice.

Alpha particles consist of two protons and two neutrons tightly bound together, which makes them compact clusters of these nucleons. This is a well-established fact in nuclear physics.

Ultraviolet (UV) light has enough energy to ionize atoms and molecules, placing it in the category of ionizing radiation rather than non-ionizing. Visible light does not have sufficient energy to ionize, and 'None' is incorrect.

Twinkling of stars occurs due to the refraction of starlight as it passes through the Earth's turbulent atmosphere, causing the light to bend and vary in intensity and position.

The escape velocity from Earth at the surface is approximately 11.2 kilometers per second, which converts to about 7 miles per second. This is the minimum velocity needed for a body to escape Earth's gravitational pull without further propulsion. Among the given options, 7 miles per second (option C) is the closest and correct value for Earth's escape velocity.

A parsec is a unit of distance used in astronomy, equal to about 3.26 light-years. It measures the distance at which one astronomical unit subtends an angle of one arcsecond.

Blue shift refers to the Doppler effect where the wavelength of light from an object decreases, making it appear bluer when the object moves towards the observer or vice versa. This is a well-established concept in physics and astronomy.