Question Discussion & Solution

The correct answer is ​Heat is absorbed.

Key Points

•  When ice is converted into water heat is absorbed by the ice, so the molecules of ice increase their energy and convert into water. Hence option A is correct.
• Additional Information
• The conversion of ice into water is an example of melting. If you took out the ice cubes from the freezer and placed them in a warm room, the ice would absorb energy from the warmer air around them. This absorbed energy would facilitate them to overcome the force of attraction holding them together, enabling them to slip out of the fixed position that they held as ice. The process in which solids change to a liquid is called melting. The melting point is the temperature at which a solid changes to a liquid. 
• The static water is converted to ice It means when the water is converted into ice its potential energy decreases. 
• If we compare the kinetic and potential energy of the water vapor, water and ice then water vapor has the most kinetic as well as potential energy as compared to water and ice.
• This is because the particle of water vapor is free to move and they can move more vigorously. Please note that kinetic energy is associated with moving objects whereas potential energy is associated with a static object. 

The correct answer is Sulphur.

• The sulphur is the eye irritating compound that is released when cutting onions.
• The syn-Propanethial-S-oxide is the chemical irritant produced by an onion.
• This chemical stimulates the eyes' lachrymal glands which release tears.
• Previously scientists used to blame enzyme alinase for the instability of substances in a cut onion.
• In 2002, a study in Japan proved that lachrymatory factor synthase is responsible for irritation of the eyes.

The correct answer is Ajmer.

Key Points​​

• Luni river:
  • The river originates at the confluence of two streams Saraswati and Sagarmati near Govindgarh of Ajmer district.
  • It flows in Ajmer, Nagaur, Pali, Jodhpur, Barmer. Jallore and drains in Rann of Kutch.
  • The water is fresh till Balotars of Barmer after that its water becomes salty.
  • The main tributaries of Luni joining from the left are the Lilri, the Guhiya, the Sukri, the Jawai, the Bandi (Hemawas), the Khari Bandi, the Sukri Bandi, and the Sagi.
  • Jojri is the only major tributary that joins the Luni river from the right.
  • The Dantiwada dam and the Sipu dam are constructed on the Luni river.
  • The main irrigation scheme in the Luni basin is Jawai dam, Jaswant Sagar dam, Hemavas, Sardar samand.

Additional Information

• Jaipur:
  • ​​Banganga, Bandi, Dhund, Morrel, Sabi are the river that flows in Jaipur.
  • Jaipur is also known as the 'Pink City', of India.
• Udaipur:
  • ​Banas, Ahar, Berach, Wakal, Gomti, Som, Jakham, Sabarmati, Sei are the river that flows in Udaipur.
• Nagaur:
  • ​​Luni, Mantha, Harsor are the rivers that flow in Nagaur.

The correct option is 2 i.e. Sodium Carbonate

Key Points

• Sodium Carbonate is also known as washing soda it is a salt of carbonic acid.
• Sodium carbonate can be manufactured by Solvay's process.
• It is used for treating hard water and industrial detergent mixtures.
• The aqueous solution of sodium carbonate is alkaline.
• Calcium Sulphate exists in the forms of white solids and is not soluble in water.
• Plaster of Paris and Gypsum are its hydrates.

Explanation:

Hygrometer:

• A hygrometer is an instrument used to measure the amount of water vapour in the air (humidity), in soil, or in confined spaces.
• Humidity measurement instruments usually rely on measurements of some other quantities such as -
  • Temperature, pressure, mass, a mechanical or electrical change in a substance as moisture is absorbed.

Additional Information

Hydrometer:

• A hydrometer is an instrument used for measuring the relative density of liquids based on the concept of buoyancy.
• They are typically calibrated and graduated with one or more scales such as specific gravity.
• Hydrometers can be divided into two general classes -
  • liquids heavier than water 
  • liquids lighter than water

A photometer is used to measure the intensity of light produced by an unknown source in terms of a standard source.

• It is an instrument that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum.
• Most photometers convert light into an electric current using a photoresistor, photodiode, or photomultiplier.
• Photometers are used to determine the correct exposure in photography.
• Photometers measure Illuminance, Irradiance, Light absorption, Scattering of light, Reflection of light, Fluorescence, Phosphorescence and Luminescence.