Question

21. Temperatures of two cities at different times are

Time →

A

B

City

At 6 AM

-3°C

271K

At 11:30 AM

300 K

27°C

AT 6 PM

5°C

270 K

On the basis of above table, answer the following questions. a) In which city, the morning temperature at 60 clock is relatively​

Answer 1

Answer:

5

SECTION – I

1. What is the resistance of a bulb which has rating as 100 W and 220 V ?

Ans. R = V

P

2 220 220

100 = 484 × = Ω .

2. Write a formula to find the focal length of a biconvex lens that is used to correct the defect of

hypermetropia.

Ans. f =

25

25

d

d − .

3. Ask one question to know the focal length of a convex lens.

Ans. What is the distance between optic centre of a convex lens and its focus ?

4. To get virtual image through a convex lens where should an object to be placed ?

Ans. Between 'F2' and 'P'.

5. What is latent heat of vapourisation of water ?

Ans. 540 cal / gr.

6. What do you observe in the given experiment,

if we switch on the circuit ?

Ans. The compass needle deflects.

7. How many ‘σ’ and ‘π’ bonds are in O2 molecule ?

Ans. One 'σ' and one 'π' bond.

8. Match the following :

a) Alkanes i) CnH2n

b) Alkenes ii) CnH2n + 2

c) Alkynes iii) CnH2n – 2

A) a – ii, b – i, c – iii B) a – i, b – ii, c – iii C) a – iii, b – i, c – ii

Ans. (A).

9. What is the maximum number of electrons that can occupy a main shell (n) ?

Ans. 2n2

.

10. What is the colour of CuSO4 ?

Ans. White.

11. Fe2O3, NaCl, HgS, CaCO3

Which of the above is an carbonate ore ?

Ans. CaCO3.

12. Li – Be – B – – N – O – F

Fill the blank box and rewrite in your answer sheet.

Ans. Li – Be – B – C – N