Tag: structure of earth

Questions Related to structure of earth

As the water is released through control valves, _____ of water changed to ____ .

biology structure of earth electricity from water energy hydro electricity hydro energy

  1. Rotational energy, potential energy

  2. Kinetic energy, potential energy

  3. Potential energy, rotational energy

  4. Rotational energy, thermal energy

Show answer
Correct Option: C
Explanation:

As the water is released through control valve, the potential energy of water changes to kinetic energy. As the water flows into reservoir from the catchment area, the kinetic energy of flowing water changes to potential energy.

Which of the following is not a purpose to build dams?

biology structure of earth electricity from water energy hydro electricity hydro energy

  1. Prevent flooding of the rivers in the area.

  2. To prevent flooding of the rivers in the area.

  3. To generate hydroelectricity.

  4. None of the above.

Show answer
Correct Option: D
Explanation:

The dams are constructed for the following purposes:
a) To prevent flooding of the rivers in the area.
b) To provide water for irrigation purposes.
c) To generate hydroelectricity.

Which of the following is not a disadvantage of building large dams?

biology structure of earth electricity from water energy hydro electricity hydro energy

  1. A vast variety of flora and fauna get submerged

  2. Dams can base dangers of earthquake

  3. Human settlement get submerged by stored water

  4. Provide water for irrigation process

Show answer
Correct Option: D
Explanation:

Providing water to irrigation process is an advantage of creating dam.

Which of the following is an advantage of building dams?

biology structure of earth electricity from water energy hydro electricity hydro energy

  1. The dams disturbs aquatic life

  2. Dams lead go large scale disturbance of aquatic life

  3. It disturbs the natural ecosystem

  4. None

Show answer
Correct Option: D
Explanation:

The dams across the Rivers can disturb the aquatic life and can lead to their large scale destruction the fishes and other water animals may enter the power generation turbines where they may get crushed.

Which of the following is not a disadvantage of building large dams for generating hydro electric power?

biology structure of earth electricity from water energy hydro electricity hydro energy

  1. Disturbance of the natural ecosystem in the surrounding forest area.

  2. Disruption of the plants and animals life.

  3. Displacement of people on a large scale.

  4. None of the above.

Show answer
Correct Option: D
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 disadvantages:

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.

Which of the following is / are disadvantage of building large dams for generating hydro electric power?

biology structure of earth electricity from water energy hydro electricity hydro energy

  1. Due to construction of dams, lot of areas of rivers having continuous fresh flowing water, have to be cleared.

  2. Number of trees have to be cut.

  3. Destroys not only the plants life but also the animals and birds life dependent on them.

  4. All of the above.

Show answer
Correct Option: D
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 disadvantages:

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.

At present, the contribution of hydroelectricity to the total power generation in India is

biology structure of earth electricity from water energy hydro electricity hydro energy

  1. A little more than $22$%

  2. A little more than $35$%

  3. A little more than $47$%

  4. None of these

Show answer
Correct Option: A

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

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

  1. $tidal$

  2. $fossil$

  3. $potential$

  4. $biomass$

Show answer
Correct Option: C
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.

Assertion : An earthquake will not cause uniform damage to all building in an affected area, even if they are built with the same strength and materials.
Reason : The one with its natural frequency close to the frequency of seismic wave is likely to be damaged less.

physics structure of earth seismic waves and tsunami causes of earthquakes origin of earth and its internal energy transfer of charge lightning safety

  1. If both assertion and reason are true and reason is the correct explanation of assertion.

  2. If both assertion and reason are true and reason is not the correct explanation of assertion.

  3. If assertion is true but reason is false.

  4. If both assertion and reason are false.

Show answer
Correct Option: C
Explanation:

An earth quake will not cause uniform damage to all building in an affected area because the natural frequencies of a building depend on its height and other size parameters and the nature of building materials.
The one with its natural frequency close to the frequency of seismic wave is likely to be damaged more.

An earthquake generates both transverse $(S)$ and longitudinal $(P)$ sound waves in the earth. The speed of $S$ waves is about $4 \,\,km \,\,s^{-1}$ and that of $P$ waves is about $8 \,\,km \,\,s^{-1}$. A seismograph records $P$ and $S$ waves from an earthquake.The first $P$ wave arrives $4$ min before the first $S$ wave. The epicentre of the earthquake is located at a distance of about

physics structure of earth seismic waves and tsunami causes of earthquakes origin of earth and its internal energy transfer of charge lightning safety

  1. $192 km$

  2. $384 km$

  3. $1920 km$

  4. $3840 km$

Show answer
Correct Option: C
Explanation:
Let $\nu _1, \nu _2$ be speed $S$ of $S$ and $P$ waves and $t _1,t _2$ be the time taken by these waves to travel to reach the seismograph. Let the epicenter of the earthquake is located at a distance $d$ from the seismograph. Then,
$d = V _1 t _1 = V _2 t _2$          ................ .....(i)
Here, $V _1 = 4 km \,\,s^{-1}$ and $V _2 = 8 km \,\,s^{-1}$
$\therefore 4t _1 = 8t _2 \Longrightarrow t _1 = 2t _2$           ....(ii)
and  $t _1 - t _2 = 4 min = 240 s$
$\therefore 2t _2 - t _2 = 240$      ....................  [using (ii)]
or $t _2 = 240 s$
put in Eq. (ii), we get,
$t _1 = 2 \times 240 s = 480 s$
From Eq. (i), we get, $d = (4 km \,\,s^{-1}) (480 s) = 1920 km$