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Multiple choice physics structure of earth electricity from water energy hydro electricity hydro energy

Destruction of large eco-systems occurs during the harnessing of.

  1. geothermal energy

  2. tidal energy

  3. wind energy

  4. hydroelectric energy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

To harness hyrdoelectric energy large hydroelectric plants are required to be built across the streams. These plants should be of very high qulaity and are expensive to build. Dams are not only costly but they also take a toll on the environment and natural habitat near it.

Multiple choice physics structure of earth electricity from water energy hydro electricity hydro energy

Which of the following are disadvantages of hydro power plant?

  1. Dams can be constructed only in a limited number of places.

  2. Large areas of agricultural land and human habitation are sacrificed

  3. Methane is released contributing to green house effect

  4. All of above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In hydro electric plants:

1. Dams are constructed in hilly areas, hence only a limited number of places.
2. Large areas of agricultural land and human habitation are sacrificed as they get submerged.
3. The vegetation which is submerged rots under anaerobic conditions and methane is released contributing to green house effect. 

Multiple choice physics structure of earth electricity from water energy hydro electricity hydro energy

Which of the following is not a limitation of hydel energy?

  1. Hydel power stations are pollution free.

  2. A vast reservoir is needed.

  3. It leads to a loss of wildlife habitat.

  4. It can be harnessed at only a few places.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For running a hydel power station throughout the year, vast amount of water  is required. This demands a vast reservoir. Such a  reservoir can be made only at a few places which are geographically suitable and do not interfere with ecosystem and human habitation.

Multiple choice physics structure of earth electricity from water energy hydro electricity hydro energy

The minimum height required to convert the stored potential energy of water into electric energy is ____.

  1. $54\ M$

  2. $34\ M$

  3. $100\ M$

  4. $5\ M$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The minimum height required to convent the stored potential energy of water into electric energy is $34\ M$ between the turbine and free energy of water in reservoir.

Multiple choice physics structure of earth electricity from water energy hydro electricity hydro energy

Fill in the blank space by choosing the correct word.
Water stored in the reservoirs of hydro-electric dams has ................. energy.

  1. $tidal$

  2. $fossil$

  3. $potential$

  4. $biomass$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Potential energy is stored energy or the energy of position. The potential energy stored in a body of water held at a given height is converted to kinetic energy (movement energy) which is used to turn a turbine and create electricity.
Hence, water stored in the reservoirs of hydro-electric dams has potential energy.

Multiple choice physics sources of energy electricity from water energy hydro electricity hydro energy

Construction of dams

  1. Is always an advantageous process

  2. Has only disadvantages

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The construction of dams for generating hydro electric power and then installation of transformers and their connection to the national grid has the following four main advantages:

A) disturbance of the natural ecosystem in the surrounding forest area

B) disruption of the plants and animals life

C) displacement of people on a large scale

D) disruption of the aquatic ecosystem.

So,construction of dams is not always advantageous.

Multiple choice physics sources of energy electricity from water energy hydro electricity hydro energy

Arrange the following steps in the conversion of hydel energy to electricity in a proper sequence.
(a) Released water is made to fall on the blades of the turbines.
(b) Water in the dam is released.
(c) Water is collected in the dam.
(d) Potential energy is converted to kinetic energy.
(e) The armature of the electric generator rotates to produce electricity.

  1. b c d e a

  2. a d b c e

  3. e c d b a

  4. c b d a e
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Initially water is collected in the dam. When it is released, the potential energy is converted to kinetic energy. The released water is made to fall on the blades of turbines. The armature of the electric generator rotates to produce electricity.

Multiple choice physics temperature and heat application of various thermometric scales different types of thermometers measuring temperature

Two thermometers are constructed in the same way except that one has a spherical bulb and the other a cylindrical bulb; which one will respond quickly to temperature changes?

  1. Spherical bulb thermometer

  2. Cylindrical bulb thermometer

  3. both equally

  4. either
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A spherical bulb has a smaller surface-area-to-volume ratio than a cylindrical bulb of similar volume, but a cylindrical bulb is often designed to have a larger surface area for faster heat exchange. However, the spherical shape is generally more robust, while the cylindrical shape responds faster due to higher surface area exposure.

Multiple choice physics temperature and heat application of various thermometric scales different types of thermometers measuring temperature

At the top of a mountain, a thermometer read ${7}^{0}C$ and barometer reads $70\, cm$ of Hg. At the bottom of the mountain, the barometer reads $76\,cm$ of Hg and thermometer reads ${27}^{0}C$. The density the density at the bottom.

  1. $0.99$

  2. $0.9$

  3. $0.89$

  4. $0.95$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using the ideal gas law P = rho * R * T. The ratio of densities rho1/rho2 = (P1/T1) / (P2/T2). P1=70, T1=280K; P2=76, T2=300K. rho1/rho2 = (70/280) / (76/300) = 0.25 / 0.2533 = 0.986, which is approximately 0.99.

Multiple choice physics temperature and heat application of various thermometric scales different types of thermometers measuring temperature

A thermometer reads $0^{\circ}$ as $10^{\circ}$ and $100^{\circ}$ as $90^{\circ}C$. Then
Find the reading of the temperature if the temperature is $40^{\circ}C$?

  1. $42^{\circ}C$

  2. $40^{\circ}C$

  3. $35^{\circ}C$

  4. $45^{\circ}C$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The scale is linear: T_new = m * T_c + c. 0 = m(10) + c and 100 = m(90) + c. Solving gives m = 100/80 = 1.25 and c = -12.5. For T_c = 40, T_new = 1.25 * 40 - 12.5 = 50 - 12.5 = 37.5. Wait, checking the math: 0C -> 10, 100C -> 90. Slope = (90-10)/(100-0) = 0.8. T_new = 0.8 * T_c + 10. For T_c = 40, T_new = 0.8 * 40 + 10 = 32 + 10 = 42.