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3 years ago

The two major parts of the optical telescope

1 answer:

5 0

The "objective" (lens or mirror) is the major major major part of
the optical telescope. It's really the only part you need in order
to make a telescope (besides something to hold the objective).
You can put a piece of film or a CCD right at the focal point of
the objective lens or mirror and capture 'images' (pictures) there.

If you want to use the telescope for looking through and seeing stuff
with your eye, then you need the other major part ... the eyepiece lens.

You might be interested in

After France fell to the Axis powers in 1940, what percentage of the country was placed under German control?

gogolik [260]

Correct answer choice is:

B. 50 percent

Explanation:

France Capitulates to Nazi Germany. On June 22, 1940, the French state approved a cease-fire with Nazi Germany just six weeks after the Nazis began their incursion of Western Europe.

Paris began preparing for combat in September 1939, when Nazi Germany overran Poland, but the combat appeared far beyond until May 10, 1940, when the Germans invaded France and immediately took the French troops. The French administration left Paris on June 10, and the Germans controlled the capital on June 14.

4 0

3 years ago

Read 2 more answers

A golfer hits a shot to a green that is elevated 3.20 m above the point where the ball is struck. The ball leaves the club at a

dem82 [27]

Answer:

16.17 m/s

Explanation:

h = 3.2 m

u = 18.1 m/s

Angle of projection, θ = 49°

Let H be the maximum height reached by the ball.

The formula for the maximum height is given by

$H=\frac{u^{2}Sin^{2}\theta }{2g}$

$H=\frac{18.1^{2}\times Sin^{2}49 }{2\times 9.8}=9.52 m$

The vertical distance fall down by the ball, h' H - h = 9.52 - 3.2 = 6.32 m

Let v be the velocity of ball with which it strikes the ground.

Use third equation of motion for vertical direction

$v_{y}^{2}=u_{y}^{2}+2gh'$

here, uy = 0

So,

$v_{y}^{2}=2\times 9.8 \times 6.32$

vy = 11.13 m/s

vx = u Cos 49 = 18.1 x 0.656 = 11.87 m/s

The resultant velocity is given by

$v=\sqrt{v_{x}^{2}+v_{y}^{2}}$

$v=\sqrt{11.87^{2}+11.13^{2}}$

v = 16.27 m/s

7 0

4 years ago

You are standing on a sidewalk. There is a car in the distance. The horn on the car sounds. You hear it at a pitch that correspo

AnnyKZ [126]

Answer: The answer: The car is moving away from you.

Both A and C are true as Car can be moving in line away from you or has component of velocity in opposite direction.

Explanation:The decrease in the frequency of the sound is the result of Doppler's effect. A/c to Doppler's effect the frequency of received sound of source is changed if it is moving relative to the receiver, i.e. the distance between them is changing due to motion.

The general formula of Doppler's Effect is attached as the picture.

In this formula v_D is the velocity of Detector i.e the receiver relative to wind. While v_s is the velocity of source relative to wind and v is the velocity of sound.

The Doppler's effect is not effected by the velocity of wind as the wind itself could not change the distance between the two objects i.e. you and the car. Wind velocity can change the speed of sound and its wavelength but the change does not effect the frequency.

Hence if we assume the car to be moving with velocity v_c and you are stationary

$f'=f_s*\frac{v}{v-v_c}$

hence the frequency is reduced.

4 0

4 years ago

An inductor has inductance of 0.260 H and carries a current that is decreasing at a uniform rate of 18.0 mA/s.

nignag [31]

Answer:

The self-induced emf in this inductor is 4.68 mV.

Explanation:

The emf in the inductor is given by:

$\epsilon = -L\frac{dI}{dt}$

Where:

dI/dt: is the decreasing current's rate change = -18.0 mA/s (the minus sign is because the current is decreasing)

L: is the inductance = 0.260 H

So, the emf is:

$\epsilon = -L\frac{dI}{dt} = -0.260 H*(-18.0 \cdot 10^{-3} A/s) = 4.68 \cdot 10^{-3} V$

Therefore, the self-induced emf in this inductor is 4.68 mV.

I hope it helps you!

6 0

3 years ago

Which material is used to reduce friction ?

Iteru [2.4K]

Answer:MOST COMMON METHOD IS USING A LUBRICANT -

A lubricant is a substance, usually organic, introduced to reduce friction between surfaces in ... medical examination. It is mainly used to reduce friction and to contribute to a better and efficient functioning of a mechanism. ... For lubricant base oil use, the vegetable derived materials are preferred

OTHER METHODS-

There are a number of ways to reduce friction:

Make the surfaces smoother. ...

Lubrication is another way to make a surface smoother.

Make the object more streamlined.

Reduce the forces acting on the surfaces.

Reduce the contact between the surfaces.

PLEASE DO MARK ME AS THE BRAINLIEST :)

6 0

3 years ago