# Physics Quiz

• #### 1. Surface tension in a liquid is due to:

2. Cohesive force between molecules
3. Gravitational force between molecules
4. Electrical force between molecules
Explanation:
Note:Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviours of liquids. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface.

# Physics Quiz

• #### 2. A boat will submerge when it displace water equal to its own

1. Weight
2. Volume
3. Surface Area
4. Density
Explanation:
Note: A boat will float when the weight of the water it displaces equals the weight of the boat and anything will float if it is shaped to displace its own weight water before it reaches the point where it will submerge. Floating of the boat works on the principle of buoyancy force which is an upward force exerted by a liquid, gas or other fluid or an object submerged in the fluid, experiences greater pressure at the bottom of the column than at the top. Thus difference in pressure results in a net force that tends to accelerate an object upward.

# Physics Quiz

• #### 3. When a barometer reading suddenly recedes, it indicates that climate-

1. will be very warm
2. will be extremely stormy
3. will remain cold
4. incessant rain for at least 48 hours.
Explanation:
Note: In summer, when the barometer falls suddenly , a thunderstorm can be expected, and if it does not rise again upon its cessation, the weather will probably continue unsettled for several days. In summer, when a thunderstorm happens, there is little or no depression of the barometer.

# Physics Quiz

• #### 4.A particle dropped from the top of a tower uniformly falls on ground at a distance which is equal to the height of the tower. Which of the following paths will be traversed by the particle?

1. Circle
2. Parabolic
3. Great Circle
4. Hyper-Parabolic
Explanation:
Note:If a particle is dropped from the top of a tower uniformly falls on ground at a distance which is equal to the height of tower then a parabolic path will be traversed by a particle because when the particle is dropped that point is called the point of projection and when it reaches the ground that point is called the point of impact. Now, if the two points is met with one another the curve emerges is parabolic in nature. Hence, we can say that the path followed by the particle is of parabolic trajectories.

# Physics Quiz

• #### 5.Which one of the following is used for sun glasses?

1. Pyrex glass
2. Flint Glass
3. Crooks Glass
4. Crystal Glass
Explanation:
Note: A type of glass that contains cerium and other rare earths and has a high absorption of ultraviolet radiation is used in sunglasses. Sunglasses are a form of protective eyewear designed primarily to prevent bright sunlight and high energy visible light from damaging or discomforting the eyes. They can sometimes also function as a visual aid, as variously termed spectacles or glasses exist, featuring lenses that are coloured, polarized or darkened. In the early 20th century they were also known as sun cheaters. The color of the lens can vary depending on style, fashion and purpose, but for general use, red, grey, green or brown are recommended to avoid or minimize color distortion, which could affect safety when, for instance, driving a car or a school bus.

# Physics Quiz

• #### 6.The speed of light with the rise in the temperature of the medium

1. Increases
2. Decreases
3. Remains unaltered
4. Drop Suddenly
Explanation:
Note: The speed of light with the rise in the temperature of the medium remains unaltered because speed of light doesn't depend on temperature. It does depend, however, on the refractive index of the substance it is travelling through. The speed of light in vacuum, commonly denoted C, is a universal physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact because the length of the metre is defined from this constant and the international standard for time. The speed at which light propagates through transparent materials, such as glass or air, is less than c.

# Physics Quiz

• #### 7. Holography is a technique of

1. recording a permanent, sharp two dimensional black and white or multicolour photograph.
2. recording a permanent three dimensional multicolor photograph
3. recording a permanent three dimensional black and white photograph
4. recording a permanent three dimensional photograph of a given single colour or a multicolour
Explanation:
Note: Holography is a technique which enables three dimensional images to be made. It involves the use of a laser, interference, diffraction, light intensity recording and suitable illumination of the recording. The image changes as the position and orientation of the viewing system changes in exactly the same way as if the object were still present, thus making the image appear three-dimensional.

# Physics Quiz

• #### 8. Boyle's Law holds good for any gas at

1. High Temperature and Low Pressure
2. High Temperature and High Pressure
3. Low Temperature and High Pressure
4. Low Temperature and Low Pressure
Explanation:
Note:At higher pressures and lower temperatures, deviation from the ideal gas behavior became noticeable , and the relationship between pressure and volume can only be accurately described employing real gas theory. Boyle's law sometimes referred to as the Boyle-Mariotte law states that the absolute pressure and volume of a given mass of confined gas are inversely proportional, if the temperature remains unchanged within a closed system.

# Physics Quiz

• #### 9.Electrostatic precipitator is used to control the pollution of

1. Air
2. Water
3. Noise
4. Thermal
Explanation:
Note:An electrostatic precipitator or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas using the force of an induced electrostatic charge. An electrostatic precipitator or electrostatic air cleaner is a particular collection device that removes particles from a flowing gas(such as air) using the force of an induced electrostatic charge. Electrostatic precipitators are highly efficient filtration devices that minimally impede the flow of gases through the device, and can easily remove fine particulate matter such as dust and smoke from the air stream. In contrast to wet scrubbers which apply energy directly to the flowing fluid medium, an ESP applies energy only to the particulate matter being collected and therefore is very efficient in its consumption of energy(in the form of electricity).

# Physics Quiz

• #### 10. The velocity of heat radiation in vacuum is

1. Equal to that of light
2. Less than that of light
3. Greater than that of light
4. Equal to that of sound