Telescopes

Q.

What is a projector? Is it possible to build the projector at home ?

Q.

The least resolvable angle by a telescope using an objective of aperture $5m$ is nearly $(\lambda =4000\AA )$

1. $\frac{1}{50°}$

2. $(1/50)$minutes

3. $(1/50)$sec

4. $(1/500)$sec

Q. The sun (diameter d) subtends an angle $\theta$ radian at the pole of a concave mirror of focal length f. The diameter of the image of sun formed by mirror is

1. $\theta f$
2. $\frac{\theta f}{2}$
3. $\theta d$
4. $\frac{\theta d}{2}$

Q.

Question 33
Draw ray diagrams showing the image formation by a concave lens when an object is placed

(a) at the focus of the lens
(b) between focus and twice the focal length of the lens
(c) beyond twice the focal length of the lens

Q.

The biggest optical telescope in India is situated at ___.

1. Mumbai

2. Delhi

3. Kerala

4. Nainital

Q.

Assertion : The resolving power of a telescope is more if the diameter of the objective lens is more.

Reason : Objective lenses of large diameter collected more light.

1. If both, Assertion and Reason are true and the Reason is the correct explaination of the Assertion.

2. If both, Assertion and Reason are true but Reason is not a correct explaination of the Assertion.

3. If Assertion is true but the Reason is false.

4. If both, Assertion and Reason are false

Q. Name the person who invented the telescope.

1. Galileo Galilei
2. Hans Lippershey
3. Homi J. Bhabha
4. Sir Issac Newton

Q. The Hubble Space Telescope was launched by the NASA in , and Chandra was launched in .

1. $1990$
2. $1992$
3. $1999$
4. $1997$

Q.

Resolving power of a telescope will be more, if the diameter a of the objective is

1. larger

2. smaller

3. resolving power does not depend upon a

4. None of these

Q.

A person wishes to distinguish between two pillars located at a distance of $11\mathrm{km}$. What should be the minimum distance between these pillars (resolving power of the normal human eye is $1$)?

1. $1\mathrm{m}$

2. $3.2\mathrm{m}$

3. $0.5\mathrm{m}$

4. $5\mathrm{m}$

Q. What is the diameter of the mirror used in the biggest optical telescope of India?

1. 3.6 m
2. 4 m
3. 2 m
4. 6.3 m

Q. When did Galileo Galilei discover 4 major moons of Jupiter?

1. 1609
2. 1610
3. 1611
4. 1612

Q.

In which of the following instruments is the final image erect?

1. Simple microscope

2. Galilean telescope

3. Astronomical telescope

4. Both (A) and (C)

Q. Which of the following is not a type of telescopes?

1. Reflecting
2. Refractive
3. Radio
4. Scattering

Q. Optical telescopes are made of_________.

1. only lenses
2. only mirrors
3. combination of lenses and mirrors
4. None of the above

Q.

In simple telescope, the lens in front of the object is known as ___________.

1. Objective

2. Reflector

3. Refractor

4. None of this

Q.

If you are standing between two mirrors and you see three images of yourself then, find out the angle at which these mirrors are inclined to each other?

1. 90°

2. 80°

3. 30°

4. 60°

Q. Galileo made the telescope in _______.

1. 1608
2. 1609
3. 1589
4. 1789

Q. Both the lenses used in a telescope are

1. convex
2. concave
3. None
4. bipolar

Q.

Name the scientist who studies the sun, moon, planets, stars etc.

Q. The focal lengths of the objective and eye lens of telescope are respectively $200cm$ and $5cm$. The maximum magnifying power of the telescope will be.

1. $-40$
2. $-48$
3. $-100$
4. $-60$

Q. A telescope gives an .............. (inverted / erect) and ........ (enlarged/diminished) image of a distant object. Choose the correct alternative.

1. Inverted, enlarged
2. Inverted, diminished
3. Erect, diminished
4. Erect, enlarged

Q. Which of the following is true for a telescope?

1. Final image is real and inverted.
2. It increases the size of the object.
3. It increases the angle subtended by image at the eye of the observer.
4. Smaller telescopes are more powerful

Q.

The instrument which is based on the principle of optics is

1. telescope

2. television

3. radar

4. solar cell

Q. The resolving power of telescope depends on

1. Focal length of eye lens
2. Focal length of objective lens
3. Length of the telescope
4. Diameter of the objective lens

Q. A small laboratory telescope has an objective lens of focal, length $140cm$ and an eye-piece of focal length $6cm$. Then, separation between the objective and eye-piece is :

1. $140cm$
2. $24cm$
3. $146cm$
4. $156cm$

Q. In a telescope the focal length of eye lens is always more than the objective lens.

Q. What are the characteristics of the final image formed by a telescope ?

Q. In a telescope, the main function of the objective lens is to collect the light coming from distant objects.

1. True
2. False

Q. Assertion :If objective and eye lenses of a microscope are interchanged then it can work as telescope. Reason: The objective of telescope has small focal length.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect