Question Discussion & Solution

CONCEPT:

• Electric Power: The rate at which electrical energy is dissipated into other forms of energy is called electrical power i.e.,

\(P = \frac{W}{t} = VI = {I^2}R = \frac{{{V^2}}}{R}\)

Where V = Potential difference, R = Resistance and I = current.

EXPLANATION:

• Mathematically power can be written as,

\(\Rightarrow P = \frac{W}{t} = VI \)

If, W = 1 J and t = 1 sec, then P = 1 watt

• Thus the power of an electric circuit is said to be one watt or 1 ampere - volt if one joule of energy is consumed in one second. Therefore option 1 is correct.

An ohmmeter is an electrical instrument that measures electrical resistance. Similarly, barometer is a scientific instrument that is used to measure air pressure in a certain environment.

The correct answer is Magnesium Sulfate.

• Magnesium Sulfate is the industrial name of Epsom.
• Magnesium sulfate is a magnesium salt having sulfate as the counterion.
• It has a role as an anticonvulsant, a cardiovascular drug, a calcium channel blocker, an anaesthetic, a tocolytic agent, an anti-arrhythmia drug, an analgesic, and a fertilizer. It is a magnesium salt and a metal sulfate.

Key Points

• Magnesium Sulfate Formula Structure:  

Additional Information

All except Yosemite National Park are in India. Yosemite National Park is in USA.

CONCEPT:

• The battery has two terminals positive and negative and its positive terminal is the cathode and its negative terminal is the anode.
  • It works on the principle of Electrochemical Reaction.
  • Italian physicist Alessandro Volta built and described the first electrochemical battery, the voltaic pile, in the year 1800.
  • The lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and mobile phones.

EXPLANATION:

• A battery converts chemical energy into electrical energy. So option 3 is correct.