Question Discussion & Solution

Concept:

Resistance: The property of electrical materials and electrical instruments that opposes the flow of current through them is called resistance.

It is denoted by R. The SI unit of resistance is the ohm (Ω).

Power: The rate of work done by an electric current is called power. It is denoted by P. The SI unit of power is the watt (W).

Power dissipation (P) is given by:

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

Where V is the potential difference across resistance, I is current flowing and R is resistance.

Calculation:

With R = 50 Ω, and V = 220 V, the power required by the bulb will be:

\(P=\frac{V^2}{R}=\frac{220\times 220}{50}\)

P = 968 W

Here the pattern is,

Pattern followed is:

Hence, “GIO” is the correct answer.

The correct answer is Solar cells.

Key Points

• A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect.
• Photovoltaic cells consist of two or more layers of semiconductors with one layer containing positive charge and the other negative charge lined adjacent to each other.
• Sunlight, consisting of small packets of energy termed as photons, strikes the cell, where it is either reflected, transmitted or absorbed.
• When the photons are absorbed by the negative layer of the photovoltaic cell, the energy of the photon gets transferred to an electron in an atom of the cell.
• With the increase in energy, the electron escapes the outer shell of the atom.
• The freed electron naturally migrates to the positive layer creating a potential difference between the positive and the negative layer.
• When the two layers are connected to an external circuit, the electron flows through the circuit, creating a current.
• Advantages of Photovoltaic Cells:
  • ​Environmental Sustainability
  • Economically Viable
  • Accessible
  • Renewable
• Disadvantages of Photovoltaic Cells:
  • ​The efficiency of solar panels is low compared to other renewable sources of energy.
  • Power generated gets reduced during cloudy weather.
  • Long-range transmission of solar energy is inefficient and difficult to carry.
  • Photovoltaic panels are fragile and can be damaged relatively easily.

The correct answer is Charles Babbage.

• Charles Babbage is considered to be the ‘Father of Modern Digital Computer’.

Key Points

• Digital computer, any of a class of devices capable of solving problems by processing information in discrete form.
  • It operates on data, including magnitudes, letters, and symbols, that are expressed in binary code—i.e., using only the two digits 0 and 1.
  • Examples of digital electronic computers include the IBM PC, the Apple Macintosh as well as modern smartphones.
• Today computers are being used almost everywhere like schools, colleges, hospitals, offices, railway stations, hotels, etc.
• A computer system is multitasking so that you can do two tasks very easily at the same time.

Additional Information

• Storage Capacity of Computer
  • Computer systems have a very large capacity to store any type of data.
  • A computer can store and resell any information due to its storage capacity. 
  • Computers have the ability to store all types of data such as data, pictures, files, programs, games, and sound for many years and later we can get any data in a few seconds at any time for taking that information and for future retrieval.
• Reliability of Computer
  • Reliability is a very big characteristic of computers.
  • Today almost all the big industries or big e-Commerce companies like Amazon and Flipkart, and big search engine companies like - Google and Bing, all these companies are dependent on computers. 
  • Today every major industry and company in the world has full confidence in their computers, and their entire business is running from computers.
• Diligence of Computer
  • A person gets tired of doing some work in a few hours and a computer has the ability to do any work continuously for many hours, days, months. 
  • Even after the computer has worked for such a long time, there is no decrease in its ability to work and its accuracy.
  • The computer does work without any discrimination.
    • A computer is free from monotony and tiredness.
• Accuracy of Computer
  • A computer is very accurate.
    • It does not make any kind of mistake in calculating.
    • Sometimes we get some errors but these are because of the mistake performed by us.
  • The Accuracy of the computer is constantly high and it can perform hundreds of operations with the carry-out calculation and analysis accurately and speedily.