Tag: evs

Questions Related to evs

While moving from deep water to shallow water.

evs magic with mirrors dual nature of light nature and sources of light theories on light

  1. Frequency of the water waves decrease

  2. Frequency of the water waves increase

  3. Frequency of the water waves stays the same

  4. None of the above

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Correct Option: C

Which of the following is a unit for intensity of light?

evs magic with mirrors dual nature of light nature and sources of light theories on light

  1. Candle power

  2. Lux

  3. Both A & B

  4. None of the above

Show answer
Correct Option: C
Explanation:
In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela (cd), an SI base unit.
Also, unit for intensity of light are:
(i) Candle Power
(ii) Lux

Which of the following statements applies to light?

evs magic with mirrors dual nature of light nature and sources of light theories on light

  1. Light can only be described as particles.

  2. Light can only be described as waves.

  3. Light can be described as rays, waves and particles.

  4. Light can only be described as rays.

Show answer
Correct Option: C
Explanation:

We can observe various phenomenon of light which cannot be explained by wave nature of light and photon nature of light some of the phenomenon are listed below:
Nature of light:                                          Phenomenon:
Ray                                                                 Reflection, Refraction
Wave                                                               Diffraction, Interference
Particle                                                  Oscillation frequency of radio waves.

Which of the following statements about the behaviour of light is not correct?

evs magic with mirrors dual nature of light nature and sources of light theories on light

  1. Interference patterns are evident for light behaving as rays.

  2. Ray properties of light are useful for understanding how images are formed by optical devices such as eyes.

  3. Wave properties are important for observing the behaviour of light at a fine scale.

  4. Both wave and particle theories of light can be related to the colour sensations produced by light.

Show answer
Correct Option: A
Explanation:

Interference patterns are explained using wave nature of light. You can learn more from youtube video "Interference of light".

Newton postulated his corpuscular theory of light on the basis of

evs magic with mirrors dual nature of light nature and sources of light theories on light

  1. newton's rings

  2. rectilinear propagation of light

  3. colour through thin films

  4. dispersion of white light into colours

Show answer
Correct Option: B
Explanation:

Rectilinear propagation of light.
According to Newton’s Corpuscular Theory of Light, light consists of very tiny particles called corpuscles. These corpuscles, on emission from the source of light, travel in straight line with high velocity.

The size of corpuscles are ________ for different colours.

evs magic with mirrors dual nature of light nature and sources of light theories on light

  1. same

  2. different

  3. either (a) or (b)

  4. None of these

Show answer
Correct Option: B
Explanation:

Different.
The corpuscles can be of different sizes. The different colors of light are due to the different sizes of the corpuscles.

According to corpuscular theory, the velocity of light in the denser medium is greater than that in rarer medium.

evs magic with mirrors dual nature of light nature and sources of light theories on light

  1. True

  2. False

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Correct Option: A
Explanation:

The corpuscles (light) would travel faster in the denser medium than in rarer medium. But later this is proved wrong. We know that light travels faster in the rarer medium than in denser medium.

The best way to conserve energy is 

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  1. Install exhaust fan at a high elevation

  2. Use of fluorescent bulbs

  3. Turn off light when not in use

  4. All of the above

Show answer
Correct Option: D
Explanation:

Conservation of energy is of great concern nowadays. Light is also a form of energy which should not be wasted. The best way to conserve the light energy are as follows.

(i) Turn off the lights when not in use.
(ii) De-dust lighting fixtures to maintain illumination.
(iii) LED Lamps should be used instead of conventional incandescent bulbs. For example, a 16w LED bulb can be as bright as 150w halogen lamp. LED lamp consumes 1/3rd of CFL energy and 1/30th energy of incandescent bulbs. 
(iv) Conventional regulators should be replaced with electronic regulators for ceiling fans.
(v) Install exhaust fans at a higher elevation than ceiling fans. In diary/poultry industry usage of multi fan axial fans leads to low energy consumption with low noise levels etc.
Thus, the correct option is D.

Identify the energy saving light bulb.

evs sources of water conservation of natural and energy resources energy conservation and sources importance of the conservation of natural resources

  1. Incandescent bulb

  2. Compact fluorescent light bulb

  3. Light emitting diode bulb

  4. Both B and C

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Correct Option: D
Explanation:

CFL (Compact fluorescent light bulbs) and LED (Light emitting diode bulb) are used in place of incandescent bulb because they use about 1/7$^{th}$ of the power used by the incandescent bulb. Hence, they are highly efficient in saving electricity.

Thus, the correct answer is option D.

Solar energy is the .......... source of energy.

evs sources of water conservation of natural and energy resources energy conservation and sources importance of the conservation of natural resources

  1. Conventional

  2. Non conventional

  3. Man made

  4. None of the above

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Correct Option: B
Explanation:

Energy generated by using wind, tides, solar, geothermal heat, and biomass is known as non-conventional energy. Solar energy is an inexhaustible non-conventional resource. There are three methods of harnessing solar energy- direct heating (e.g., solar cookers), thermoelectric conversion or solar thermal power plants, for example, steam generation and photovoltaic conversion.

Thus, the correct answer is option B.