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The length of a telescope is 36 cm . The...

The length of a telescope is 36 cm . The focal lengths of its lenses can be

A

30 cm, 6cm

B

`-30cm, -6 cm`

C

`30cm, -6cm`

D

`-30cm, 6cm`

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The correct Answer is:
A
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NCERT FINGERTIPS-PRACTICE PAPPER-Practice Paper 3
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  4. A positively charged thin metal ring of radius R is fixed in the xy pl...

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  5. A voltmeter having a resistance of 1800 Omega employed to measure the ...

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  7. A 100 W bulb B(1) and two 60 W bulbs B(2) and B(3), are connected to a...

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  8. A short conducting rod P of length 3.0 cm is placed parallel to an nea...

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  9. A rectangular loop carrying a current i is situated near a long strai...

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  11. A gang capacitor is formed by interlocking a number of plates as shown...

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  12. A galvanometer of resistance 25Omega is connected to a battery of 2 vo...

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  13. A rectangular coil of 20 turns and area of cross-section 25 cm^(2) has...

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  14. For perfectly coupled coils, the coupling coefficient should be equal ...

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  15. A 200 muF capacitor in series with a 100 Omega resistance is connected...

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  16. The efficiency of a transformer is 90%. The transformer is rated for o...

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  17. In an experiment to find focal length of a concave mirror, a graph is ...

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  18. In a reflecting astronomical telescope, if the objetcive (a spherical ...

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  19. Which one of the following is a possible nuclear reaction ?

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  20. A 5 W source emits monochromatic light of wavelength 5000 Å. When plac...

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  21. Calculate in how many months , (3/4)^(th) of the substance will dacay,...

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