Modern Physics and Electronics
Knowledge-based Questions:
1. What is radioactivity?
Answer: Radioactivity is the emission or transmission of ion in the fome of way so spariales trisen seaton of atomic nuclei.
2. What is Becquerel?
Answer: The unit used for measuring radioactivity is Becquerel.
3. What is half-life?
Answer: The time in which half of the nucleus disintegrates (or radiates) is known as half life.
4. What is an analog signal?
Answer: The continuously changing data can be converted into electrical signals and these types of signals are called analog signals.
5. What are the electronics?
Answer: Electronics is the controlled electric flow through the vacuum tube, a special type of callus and chips.
6. Give an example of p-type semiconductor.
Answer: The semiconductor formed by adding boron with silicon is an example of p-type semiconductor.
7. What is p-n junction diode?
Answer: The junction created by joining a p-type and a n-type semiconductor is called p-n junction diode.
8. What is an amplifier?
Answer: Amplifier is an electronic device for increasing the amplitude of electrical signals.
9. What is semiconductor?
Answer: Semiconductors are materials that have electric conductivity higher than insulator and lower than the conductor.
10. What is a diode?
Answer: The junction created by joining a p-type and an n-type semiconductor is called a diode.
11. What is a p-type semiconductor?
Answer: p-type semiconductor is a semiconductor created by adding trivalent atoms with a pure semiconductor.
12. What is a communication device?
Answer: A communication device is any type of hardware capable of transmitting data, instructions, and information between a sending device and a receiving device.
13. What is a microphone?
Answer: The electronic device which people use to deliver their speeches in various programs or seminars is called a microphone.
14. What is a fax?
Answer: The machine that is used to send a copy of any document and can print a document that is sent at the same time is called a fax.
15. What is the modulation?
Answer: Modulation is the process of superimposing a high-frequency electromagnetic wave over the sound wave.
16. What is a computer?
Answer: Computer is an electronic device that can receive, process, transfer, store, and transmits data.
17. What is a speaker?
Answer: The device which converts an electric signal into a sound signal is called the speaker.
18. What is internet?
Answer: The Internet is a global wide area network that connects computer systems across the world.
19. What is e-mail?
Answer: E-mail is the short form of electronic mail. The exchange of digital information with one or many persons using the internet, with the help of digital devices such as computer, tablet etc. is called e-mail.
Comprehension-based Questions:
1. What do you understand by integrated circuit? Explain.
Answer: For the design of electronics, diode, transistor, resistor, capacitors, etc. are connected using wires.
Generally, this circuit is large. To reduce the size, circuits are designed in the nanoscale. These circuits are called integrated circuit or ICs.
2. Write down the function of a chip.
Answer: The placement of numerous electronic circuit in a single motherboard is difficult. That is why IC or chip was invented. The silicon or semiconductor structure having small cells composed of microlevel circuits is called a chip.
3. Write down the advantage and disadvantage of analog and digital signals.
Answer: Advantages and disadvantage of analog and digital signals are:
i) Digital signal is preferable for transmitting data at a distant location. With the increase in distance the transmitting power of analog signal decreases. In case of the digital signal, the signal is amplified automatically. Therefore, information is preserved.
ii) Digital signal is used for optical transmission. As a result, the information is preserved.
iii Digital signals can transfer a large amount of information within a short time.
iv) Cross-connection may occur in the analog signal. There is no possibility of cross-connection in digital signal.
4. Why the extrinsic semiconductors are electrically neutral?
Answer: Generally, the conduction band is empty and the valance band is almost complete in semiconductors. As a result, electron transfer does not take place. However, if they are doped then the electrons may jump from the valance band to the conduction band. Here, transfer of electron from other atom does not take place or they do not become ionized. So, the semiconductors are neutral.
5. What is meant by the half-life of radioactive element?
Answer: The time in which half of the nucleus disintegrates (or radiates) is known as the half-life. The more the radioactivity of an element, the less its half-life is. The half-life of a stable nucleus having no radioactivity can be considered to be “infinity”.
6. Why it is suitable to use optical fiber to send electrical signal at long distance? Explain.
Answer: Infrared rays of long wavelength are used in optical fibers. Because of using infrared rays, the absorption of light in optical fibers is very low and light can be taken hundreds of kilometers through optical fibers. Infrared light propagates through the fiber with much lower attenuation compared to electrical cables. That is why; it is suitable to use optical fiber to send electrical signals at long distances.
7. Write down differences between analog and digital signal.
Answer: Differences between analog and the digital signal are given below-
Analog Signal | Digital Signal |
1. Current or voltage changes continuously in analogue signal. | 1. Current or voltage changes discretely in digital signal. |
2. Analog signal can be represented using a Sine wave. | 2. Digital signal can be represented using a square wave. |
3. Analog signal contains all the values between the maximum and minimum value. | 3. Digital signal contains only some fixed values. |
8. Explain the difference between alpha and beta particles.
- Alpha particle refers to helium nucleus while beta particle refers to electron flow.
- Beta particle has a very high penetrating power in comparison to alpha particles.
- Alpha particles are far less harmful than beta particles.
- The mass of an alpha particle is equal to that of a hydrogen atom while the mass of a beta particle is equal to that of an electron.
- The charge of an alpha particle is + 3.2 × 10-19 coulomb while that of a beta particle is -1.6 × 10-19
- Alpha particle has a velocity measuring one-tenth of the velocity of light while beta particle has a velocity measuring 50% to 98% of the velocity of light.
Creative Questions
Creative Question 1: A student of class ten Samrat has gone to Ruppur of Pabna for study tour. He observed the mechanism of energy production in nuclear reactor there.
c) How energy is produced in the place seen by Samrat? Describe.
d) How much logical the mechanism of the production of that energy in Bangladesh? What do you think about it.
[C.B-2020]
Creative Question 2:
c) How does the semiconductor of’A’ figure form?
d) How do electrons pass through the junction of figure ‘C’? Explain with circuit connection.