ASTU SS PHYSICS CHANNEL

Q_1 Compute the net torque exerted at the center of the circle for the diagram labeled below.

Example 4: A wheel has a radius of 20 cm and accelerates from rest to 15 rev/s in 30 s. What is the magnitude of the tangential acceleration of a point at the tip of the wheel?

Kidus share to your class students

https://docs.google.com/forms/d/e/1FAIpQLSfsRJjH8l6E5Wl2LNNz1FzBTK7VDl5q-p6wnCWhLj-5u07ENg/viewform

Urgent Notice for our students!!!
_______
Students who want to be the member of Questions and Answers Club you can register online through the link posted below.

s to destroy cancer cells
- D) A chemotherapy regimen

20. Which imaging technique is commonly used to plan radiation therapy?
- A) MRI (Magnetic Resonance Imaging)
- B) CT (Computed Tomography)
- C) PET (Positron Emission Tomography)
- D) All of the above

Class Work for 24-01-2017 E.C

1. In which situation would an X-ray be preferred over an MRI?**
- A) For assessing brain injuries
- B) For viewing bone fractures
- C) For evaluating soft tissues
- D) For detecting tumors

2. What is the primary function of a radar transmitter?
- A) To amplify received signals
- B) To generate and emit radio waves
- C) To process radar data
- D) To display radar images

3. Which principle does radar use to determine the distance to an object?
- A) Doppler effect
- B) Time of flight
- C) Frequency modulation
- D) Amplitude modulation

4. Which of the following applications is NOT typically associated with radar technology?
- A) Weather forecasting
- B) Speed enforcement by police
- C) Medical imaging
- D) Air traffic control

5. What is the primary function of radar signal processing?
A) To generate radio waves
B) To filter out noise and enhance target detection
C) To transmit data to other systems
D) To measure the temperature of the target

6. What is the main advantage of using 5G technology over previous generations?
- A) Increased latency
- B) Higher data transfer speeds
- C) Reduced coverage area
- D) Lower frequency bands

7. What is the primary difference between cruise missiles and ballistic missiles?
- A) Cruise missiles are powered throughout their flight, while ballistic missiles are powered only during the initial launch phase.
- B) Ballistic missiles can change direction mid-flight, while cruise missiles cannot.
- C) Cruise missiles are generally larger than ballistic missiles.
- D) Ballistic missiles are used for air-to-air combat, while cruise missiles are used for ground attacks.

8. Which of the following is a typical range for a cruise missile?
- A) Less than 100 km
- B) 100 km to 1,000 km
- C) 1,000 km to 5,500 km
- D) More than 5,500 km

9. Which of the following statements about ballistic missiles is true?
- A) They fly at low altitudes throughout their flight.
- B) They are generally faster than cruise missiles.
- C) They can be launched from mobile platforms only.
- D) They are designed for tactical engagements only.

10. Which type of missile is often used for precision strikes against land targets?
- A) Tactical Ballistic Missiles
- B) Strategic Ballistic Missiles
- C) Cruise Missiles
- D) Intercontinental Ballistic Missiles

11. What is the primary guidance system used by most cruise missiles?
- A) Inertial navigation
- B) GPS
- C) Terminal homing
- D) All of the above

12. In which application are infrared night vision systems most commonly used?
- A) Astronomy
- B) Military surveillance
- C) Underwater exploration
- D) Weather forecasting

13. What is the primary function of infrared detectors in night vision technology?
- A) To amplify visible light
- B) To detect heat emitted by objects
- C) To filter out UV light
- D) To enhance color contrast

14. What is the main advantage of using infrared detection for night vision over traditional optical systems?
- A) Higher resolution
- B) Ability to see in complete darkness
- C) Enhanced color reproduction
- D) Longer battery life

15. What is the term for the total amount of radiation delivered to a patient over the course of their treatment?
- A) Dose
- B) Fractionation
- C) Exposure
- D) Volume

16. Which type of radiation is most commonly used in external beam radiation therapy?
- A) Alpha particles
- B) Beta particles
- C) X-rays
- D) Infrared rays

17. What is the primary purpose of radiation therapy in cancer treatment?
- A) To cure all types of cancer
- B) To shrink tumors and kill cancer cells
- C) To relieve pain only
- D) To replace surgery

18. Which of the following is a common side effect of radiation therapy?
- A) Hair loss
- B) Increased appetite
- C) Improved energy levels
- D) Enhanced immune response

19. What is brachytherapy?
- A) A type of external beam therapy
- B) A technique where radioactive sources are placed inside or close to the tumor
- C) A method that uses laser

INFRARED WAVE DETECTION FOR NIGHT VISION

Human eyes can detect only the optical (visible light) range of spectrum.

@ All people, places and things give off infrared light in amount proportional to their temperature.

@Infrared devices typically use heat emissions to identify objects that cannot be detected using available light sources.

@Thermal imaging system creates an electronic image based on the temperature differences in the radiating object; hotter objects appear brighter than cooler objects.

infrared wave detection technology can enable the creation of night vision devices like goggles, cameras, or scopes that provide enhanced visibility in low-light conditions.

@Temperature difference in the target is represented by different colors that are not related to the actual color of the target.

Physics In Communication

Communication is the process of transferring information from one place to the other using physical wire or without wire)

@Most of the communication technology uses the EMR physics like Reflection, Refraction, Compression, Diffraction, Interference, Rarefaction , Propagation, and Transmission.

@Wire communication needs physical cables to transmit data between devices.

Examples:

Twisted Pair Cables, Coaxial Cables and Fiber Optic Cables.

@Wireless communication system transmits data through EMR without the need of physical connections.

Examples:

Radio waves, Microwaves, Infrared waves, Wifi and Bluetooth.

Radar

stands for "Radio Detection and Ranging," is a technology that uses radio waves to detect and locate objects. It is commonly used in various fields, including:
@aviation
@weather monitoring
@military applications, and @automotive systems.

Main Purpose

The main purposes of radar include:

1. Detection: Identifying the presence of objects, such as aircraft, ships, or weather formations.

2.Tracking: Monitoring the movement of objects over time, which is crucial for navigation and security.

3.Range Measurement: Determining the distance to an object.

4.Speed Measurement: Calculating the speed of moving objects, often used in law enforcement.

Working Principle

The basic working principle of radar involves the following steps:

1.Transmission:
A radar system emits a pulse of radio waves through an antenna.

2.Reflection:
When these waves encounter an object, some of the energy is reflected back toward the radar system.

3.Reception:

The radar antenna receives the reflected waves.

4.Signal Processing:

The radar system analyzes the received signals to determine various characteristics of the object, such as its distance, speed, and direction.

Key Components

1.Transmitter: Generates the radio waves.

2.Antenna: Sends and receives the radio waves.

3.Receiver: Captures the reflected signals.

4.Display/Processor: Analyzes and presents the data to the operator.

Concepts of Physics Used

@Electromagnetism
@Wave Theory
@Signal Processing
@Electronics
@Propagation of EMW
@Doppler Effect
@Solid State Physics

Stethoscope & Ultrasound
A stethoscope is a medical instrument used by healthcare professionals to listen to internal sounds of a patient’s body, in diagnosing conditions related to the heart, lungs, and other organs by amplifying internal sounds.

Aids in evaluating the function of the cardiovascular and respiratory systems.

Ultrasound
An ultrasound (Sonography) machine is a medical device that uses high-frequency sound waves to create images of organs and structures inside the body.

Used in

1. Pregnancy Monitoring
2. Abdominal Imaging
3. Cardiac Ultrasound
4. Musculoskeletal Imaging

How It Works

1. The transducer sends sound waves into the body.
2. These waves bounce off tissues and organs, creating echoes.
3. The machine processes the echoes to produce images on the monitor.

In ultrasound imaging, the terms:anecoic, hypoechoic, and hyperechoic describe the appearance of different tissues or regions based on how they reflect sound waves.

Anechoic
Dark (no echoes, e.g., fluid)

Hypoechoic
Darker than surrounding tissues (e.g., some tumors)

Hyperechoic
Brighter than surrounding tissues (e.g., bones, calcifications)