Initially at start of heating from 0°C to 4°C there will be a contraction as a result of which volume decreases. On further heating beyond 4°C to 10°C the molecules gain kinetic energy and start moving more randomly. Thus, intermolecular distance increases as a result of which its volume increases.

The loss of heat is directly proportional to the surface area, hence loss of heat will be earlier in case of sphere because it has the maximum surface area.

Only statement 3 is correct. An air conditioner (often referred to as AC) is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. Steam (at 100 degree Celsius ) has more energy than water ( at 100 degree Celsius ) because it takes energy to break the bonds that keep it liquid. Latent heat is the heat released or absorbed by a chemical substance or a thermodynamic system during a change of state that occurs without a change in temperature. Latent heat of fusion of water is 334 kJ/kg whereas Latent heat of vaporization of water is 2260 kJ/kg.

Cloudy nights are warmer than clear nights because, the cloud cover provides a shield which act as an insulator and store up the heat radiated by the earth and do not permit heat to escape.

The anomalous expension of water as it cools from 4°C to 0°C means that the density of water is greatest at 4°C. So the ice that forms in cold weather forms at the top of the water (where the less dense coldest water gathers) and then acts as an insulating barrier preventing the water underneath from getting much colder (because heat cannot escape).

Sounds may be generally characterized by pitch, loudness, and quality. Sound “quality” or “timbre” describes those characteristics of sound which allow the ear to distinguish sounds which have the same pitch and loudness. Quality is then a general term for the distinguishable characteristics of a tone.

This is a phenomenon of total internal reflection of light, dependent on the`critical angle’ of the incidence of light in a material medium at its bounding surface with air. The higher the refractive index of a transparent material the smaller is the critical angle and hence the larger is the range of angles of incidence for more light to be totally reflected. A diamond has a large refractive index and very small critical angle as against glass, which has a lower refractive index and large critical angle. A skilled diamond cutter exploits the large range of angles of incidence in the diamond to cut multiple faces at suitable angles. Light entering diamond from different faces, suffers multiple total internal reflection and comes out of the diamond as intense beams from selected directions. Hence, a diamond shines brilliantly.

An optical fibre is a thin, flexible, transparent fibre that acts as a waveguide or “light pipe” to transmit light between the two ends of the fibre. An optical fibre transmits light along its axis, by the process of total internal reflection. When light traveling in a dense medium hits a boundary at an angle larger than the “critical angle” for the boundary, the light will be completely reflected. This effect is used in optical fibres to confine light in the core.

Air bubble in water would act as a diverging lens, because the index of refraction of air is less than that of water.

Consider a plane-mirror and a fixed incident ray of light. Before the mirror has rotated, the angle of incidence is θ as is the angle of reflection. If the mirror is rotated through an angle ϕ the normal is rotated by an angle f and thus the angle of incidence increases to θ + ϕ. Therefore, the angle of reflection must also increase by ϕ to θ + ϕ. The difference between the final angle of reflection and the initial angle of reflection is 2ϕ. Thus for a fixed incident ray, the angle of the reflection is twice the angle through which the mirror has rotated.

Total internal reflection is an optical phenomenon that happens when a ray of light strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. If the refractive index is lower on the other side of the boundary, no light can pass through and all light is reflected. The critical angle is the angle of incidence above which the total internal reflection occurs. Total internal reflection takes place when light travels from optically denser medium to optically rarer medium. Refractive index of diamond is very high (2.417) whereas refractive index of glass is only in between (1.5 to 1.6), whereas in rest all options there is no possibility of total internal reflection because refractive index of water (1.33) and air (1.0008) is less than refractive index of glass.

Mach number (Ma or M) is the speed of an object moving through air, or any other fluid substance. It is commonly used to represent the speed of an object when it is travelling close to or above the speed of sound. Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. The SI unit for pressure is the pascal (Pa), equal to one newton per square meter (N/m²).
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave’s shape repeats. The unit for wavelength is the angstrom.
In physics, energy is a quantity that is the ability to do work. In the International System of Units (SI), energy is measured in joules, but in some fields other units such as kilowatt-hours and kilocalories are also used.

Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one medium to another at any angle other than 90° or 0°. Refraction of light is the most commonly observed phenomenon. In both cases the phenomenon of refraction is applicable because there will be a change in the direction and speed as light enters from one media to other. In case 1 light for observer outside water the light ray is travelling from denser medium (water) to rarer medium (air). Thus, image of coin will appear closer due to refraction. Whereas in case 2 for observer under water refraction also takes place but in opposite way as light travels from rarer medium (air) to denser medium (water) .Thus, the image of coin will appear at a higher level than actual position of coin.

The decibel is widely known as a measure of sound pressure level, but is also used for a wide variety of other measurements in science and engineering. The decibel is commonly used in acoustics to quantify sound levels relative to a 0 dB reference which has been defined as a sound pressure level of .0002 microbar. The noise level of 100 decibel would corresponds to noise from a machine shop.

A is correct but an image formed on the retina of eye persists for about (1/16) sec(0.06 sec) after it changes.

Both of the statements are correct and statement 2 is also correct explanation for statement 1. Total internal reflection is an optical phenomenon that happens when a ray of light strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. If the refractive index is lower on the other side of the boundary, no light can pass through and all of the light is reflected. Thus because of this phenomena traffic light beads glow when light falls on them.

The reason CDs reflect rainbow colors is because they have a clear plastic coating on top of a mirrorized surface. Light refracts (bends) when it moves from one medium (such as air) to another with a different optical density (such as the clear plastic surface of a CD). Different wave lengths of light (every color has a different wave length) travel at different speeds, so that full spectrum appears when white light passes from the air through the plastic surface of a CD, separated light rays which are then reflected back to us by the mirrorized center surface of a CD. Here the diffraction and transmission also takes place because diffraction of light rays occur when it strikes the surface of CD and transmission is obvious when light enters from one medium to another. The thickness of the different optical media, angle of source light, and brightness of source light all affect which rainbow patterns are visible on a CD.

Statement 1 is true but statement 2 is false. Yes the stick dipped in water appears to be bent and short but refraction of light by water molecules is the phenomena responsible for this observation not because of scattering of light.

When light enters from rarer (air) to denser (glass) medium wavelength and velocity will get affected. The velocity will decrease. Moreover, as the ray bent in passing through different media which results in decrease of wavelength. As such there is no change in frequency when light enters from air to glass.