Questions

Magma is injected into surrounding rock forming an igneous intrusive.

Actually it is a plutonic formation in which magma present beneath Earth surface deforms the shape of rocks present above it
 

Fathometer is used to measure the depth of the ocean.

Accoustics is a subject deals with the Study of sound

Aesthetics is a Philosophy of fine arts

The science or art of flight is called Aeronautics

The science of soil management is called Agronomy.

Arya Samaj was an Indian religious movement  based   on   Vedas  and was     founded     by     Dayananda Saraswati on April 7, 1875 and was based in Punjab and western Uttar Pradesh     states     like,     Aligarh, Varanasi, etc.  It  was  against  caste system  and  supported  equality  of men   and   women,moreover   it mainly    comprised    the    trading castes;    while    Brahmo    Samaj, founded  by  Raja  Rammohan  Roy, was limited because it was popular only   among   elite   and   educated society.

1st copper wire: R = pl/A = pl/ πr2

2ndcopper wire: R’ = p’l’/A’ = pl/(4 πr2) = R/4

If joined in parallel, (1/Req) = (1/R) + (1/R’)

= 1/R + 4/R1/Req= 5/R

Req= R/5

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.