Question Discussion & Solution

i) Point B is 3m North of point A.

ii) Point C is 3m West of point B.

iii) Point D is 5m South of point C.

iv) Point E is 7m East of point D.

Drawing the Diagram as per the given information:

Thus we can se direction of E is South-East with reference to point B.

Hence, the correct is "South-East".

The pattern followed here is:

25 → First digit of 23 and second digit of 65.

68 → First digit of 61 and second digit of 38.

? → First digit of 72 and second digit of 48 → 78.

Hence, the answer is 78.

Bleaching powder:

• Calcium hypochlorite is known as bleaching powder.​
• It is a pale yellowish powder having a strong smell of chlorine.
• It is soluble in cold water.
• Bleaching powder reacts with dilute acids to produce chlorine.
• When bleaching powder is treated with an excess of a dilute, all the chlorine present in it is liberated.
• It is used in bleaching clothes in the laundry due to its oxidizing property.

Formula- CaOCl₂ 

Additional Information

• Washing powder: The chemical name of washing soda is Sodium carbonate Decahydrate and the chemical formulae is Na_2​CO3​.10H_2​O.
• Baking powder: Sodium hydrogen carbonate is the chemical term for the baking powder with chemical formulae NaHCO₃.
• Soda ash: Anhydrous Sodium carbonate is known as Soda ash with chemical formulae Na₂CO₃.

The correct answer is chemical energy.

Key Points

• The dry cell is a type of electric battery which is used for portable electrical devices.
• Electricity is produced through the dry cells from electrochemical energy. Hence, Option 1 is correct.
• A common dry cell is a zinc-carbon cell.
• The electrolyte is immobilized as a paste by a dry cell, with just enough humidity in it to allow current to flow.
• Like a wet cell, a dry cell can work without spilling in any direction, because there is no free liquid in it.
• The versatility makes it ideal for mobile devices.
• The first wet-cell batteries, in comparison, were usually fragile glass containers featuring lead rods sticking from an open-top.
• Hence, they required careful handling to prevent spillage.
• The dry-cell battery development made a significant advance in battery safety and portability.
• Batteries render electricity from chemical energy.
• Batteries consist of one or more different parts, or cells, which contain an electrolyte called a chemical.
• Every cell has two electrodes that are electrically conductive immersed in its electrolyte.
• The electrodes consist of different materials; one releases electrons into the electrolyte, and the other absorbs them.
• Once an electrical system is attached to the electrodes, an electrical current passes through it and supports its operation with electric power.
• The energy contained in the dry cell is therefore in the form of chemical energy.

Additional Information

• Thermal energy
  • It is also called heat energy 
  • It is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.
  • The energy that comes from the temperature of the heated substance is called thermal energy.
  • Thermal energy is energy that comes from a substance whose molecules and atoms are vibrating faster due to a temperature rise.
• In physical sciences, mechanical energy
  • It is the sum of potential energy and kinetic energy.
  • It is the macroscopic energy associated with a system.
  • The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is constant.
• Nuclear power
  • It is the use of nuclear reactions to produce electricity.
  • Nuclear power can be obtained from nuclear fission, nuclear decay, and nuclear fusion reactions.
  • Presently, the vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium in nuclear power plants.

The correct answer is Distance.

Key Points

• An odometer is a device that is used for measuring the distance traveled by a vehicle.
• The odometer is usually situated in the vehicle's dashboard.
• The word "odometer" is derived from two Greek words meaning path and measure.
• Odometer is also used by people who construct roads and survey lands.

Additional Information