Question

1-Name any four regions of electromagnetic spectrum in increasing order of frequency

2-Calculate the amount of heat given out while 400 g of water at 30 °C is cooled and converted into ice at -2 °C. Specific heat capacity of water = 4200 J/kg K Specific heat capacity of ice = 2100 J/ kg K Specific latent heat of fusion of ice = 336000 J/kg.

Proper explanation please!

Answer 1

a) increasing order of frequency of electromagnetic spectrum , ----
Ultraviolet rays < X-rays < Gama -rays <cosmic rays

b) water first increase 0°C temperature let H1 heat required
H1 =mSdT
=400/1000 x 4200 x (30°-0°)
= 40 x 42 x 30
=1200 x 42
=50400 Joule

now , water change phase ,
H2 =mLf
=400/1000 x 336000
=4 x 33600 Joule
=134400 Joule
now ice decrease temperature from 0°C to -2°C
H3 =mS"dT
=400/1000 x 2100 x 2
= 4 x 210 x 2
=8 x 210 =1680 Joule

now ,
total heat =H1 + H2 + H3
=186480 Joule

Answer 2

Hola mate..

Answer:-

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