Questions

A mixture is made from different substances that are not chemically joined.Compound:

•Two or more elements combine together chemically to form a new substance called compound.

•The different elements are chemically joined together.•Compounds are homogeneous, i.e. their properties are the same throughout

•The compound has properties different from the elements it contains.

•It can only be separated into its elements using chemical reactions. (not using physical methods)

•During the formation of a compound from its elements, a certain amount of energy in the form of heat, light, electricity is either absorbed or evolved

The mesosphere lies above the stratosphere and extends to an altitude of about 85 km. This is layer is often referred to as the cold layer, as the lowest readings in the atmosphere are found here.

Temperature decreases with height, reaching a minimum average value of -90 ºC at the top of the layer.

I am ABBREVIATION.

Yes, i make things short and asks the full form of that thing.

Ex : FCI - Food Corporation of India

IAS - Indian Administrative Service.

When you compress or stretch a spring, as soon as the stress is relieved, the spring attains its normal shape instantly. Its Elastic potential energy helps it do so. Generally, these elastic substances follow the Hooke’s law.

According to this Law, the force needed to change the shape of spring is proportional to the displacement of the spring. The displacement referred here is how far the spring is compressed or stretched from its normal shape. Mathematically, Hook’s Law can be summarised as F= – k x. Here ‘k’ is the spring constant and ‘x’ is the displacement.

Black  surfaces are good emitters of heat ( They are also good absorbers of heat). If the black surface is rough too, the emitting will be better. So (b) is the correct answer. Shining surfaces reflect back radiation. So if the black surface is also shining the effectiveness of emitting heat is lessened.

1) G.V. Mavalankar (1952-56)

2) M.A. Ayyangar (1956-57 & 1957-62)

3) Hukam Singh (1962-67)

4) N. Sanjiva Reddy (1967-69)

5) Gurdial Singh Dhillon (1969-1971 & 1971-1975)

6) Bali Ram Bhagat (19976-77)

7) K.S. Hegde (1977-80)

8) Balram Jakhar (1980-1984 & 1984-1989)

9) Rabi Ray (1989-91)

10) Shivraj Patil (1991-96)

11) P.A. Sangma (1996-98)

12) G.M.C. Balayogi (1998-99 & 1999-2002)

 13) Manohar Joshi (2002-04)

14) Somnath Chatterjee (2004-09)

15) Meira Kumar (2009-14)

16) Sumitra Mahajan (2014-19)

17) Om Birla (2019 -)