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zzz [600]
3 years ago
5

What is principal focus and focus length with examples​

Physics
1 answer:
Shkiper50 [21]3 years ago
7 0

Explanation:

Principle focus is the point on the axis of a convex lens, where the parallel rays of light from one side of the lens. meet on other side after refraction. Distance between optical centre to principle focus point is the focal length.

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2. Neutrons have a ____<br> charge.<br> a. positive<br> b. negative<br> c. neutral
AnnyKZ [126]

Answer:

b. negative

Explanation:

neutrons have a negative charge and protons have a proton has a positive charge

3 0
3 years ago
Read 2 more answers
A car changes speed from 25 m/s to 10 m/s in 240 seconds. Describe its acceleration.​
Dmitry_Shevchenko [17]

Explanation:

Acceleration is change in velocity over change in time:

a = Δv / Δt

a = (10 m/s - 25 m/s) / (240 s - 0 s)

a = -0.0625 m/s²

So the car decelerates at 0.0625 m/s².

7 0
4 years ago
The engine in your car is sometimes called: A. A 2-stroke engine
Juli2301 [7.4K]

Answer:A

Explanation:

Engines in car are 4 stroke engine . A 4-stroke engine is internal combustion engine which derives its power by four piston strokes . Internal combustion means combustion takes inside the engine i.e. is in cylinder.

There are process in 4 stroke engine

  • Intake: Intake of air
  • Compression:compression of intake air to a high pressure
  • Combustion:Fuel is injected and burned to get power
  • Exhaust:removal of exhaust gases after combustion    
7 0
3 years ago
Which best describes why scientific models change over time?
irina1246 [14]
Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.

Below are the choices and the answer is <span>B. 
</span>a.) Models can be changed by scientists who are more famous than previous scientists. 
<span>b.) As technology advances, new experiments often expose problems in accepted theories. </span>
<span>c.) Scientists tend to value new theories because they are more exciting. </span>
<span>d.) A newer theory is more valid because it uses more mathematics. </span>

6 0
4 years ago
What is the difference between internal and external force
AnnZ [28]

Answer:External forces are forces caused by external agent outside of the system. Internal forces are forces exchanged by the objects in the system.

Explanation:or our purposes, we will simply say that external forces include the applied force, normal force, tension force, friction force, and air resistance force. And for our purposes, the internal forces include the gravity forces, magnetic force, electrical force, and spring force.HOPE THIS HELPS!!! ^w^

7 0
3 years ago
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