Option (d) is correct. 800 calories of heat is released.
Explanation:
The formula for the heat is given by
Q= m L
Q= heat energy
m= mass =10 g
L= latent heat of fusion=80 cal/gram
so Heat energy= Q= 10 (80)=800 cal
the heat energy is released.
so 800 calories of heat is released.
Answer: R = 28 degree
Explanation:
The given parameters are:
Refractive index n = 1.52
Incident angle I = 45 degree
According to Snell law,
Sin I/Sin R = n
Where
I = angle of incidence
R = angle of refraction
n = refractive index
Substitute all the parameters into the formula
1.52 = sin 45/ sin R
Make sinR the subject of formula
Sin R = sin 45/1.52
Sin R = 0.46520
R = sin^-1(0.46520)
R = 27.72 degree
Therefore, the angle of refraction will be 28 degrees approximately.
Answer:
1. Potential hazard
2. Mining opportunity
Explanation:
The two reason, why astronomers are so interested in the discovery of additional Earth-approaching asteroids:
1. Potential hazard: We have proof that the dinosaurs got extinct because of an asteroid/comet strike on Earth. Also we have seen the effects of the Tunguska event and Chelyabinsk tragedy. These are enough to show us that asteroids can be very dangerous and wipe out the life from Earth.
2. Mining Opportunity: We have discovered a lot of asteroids which contains a lot of metal and precious elements. There can be a possibility of mining such asteroids in the future and reducing the burden on Earth.
Answer:
F = M2 ω^2 R centripetal force of sun on planet
ω = (F / (M2 R))^1/2 = 2 pi f = 2 pi / P where P is the period
P = 2 pi (M2 * R / F)^1/2
F = G M1 M2 / R^2 gravitational force on planet
P = 2 pi {R^3 / (G M1)]^1/2
P = 6.28 [(2.0E11)^3 / (6.67E-11 * 3.0E30)]^1/2
P = 6.28 (8 / 20)^1/2 E7 = 3.9E7 sec
1 yr = 3600 * 24 * 365 = 3.15E7 sec
P = 3.9 / 3.2 = 1.2 years