5.4 x 1014Hz
wavelength x frequency = the speed of light
The surface temperature of the star increases when it changes its colour changes from red to blue.
Blue>white>yellow>orange>red
The given series is the temperature decreasing order of stars. Now our sun is considered as a yellow star.
Answer: Option (d) is the correct answer.
Explanation:
A chemical reaction in which heat energy is liberated is known as an exothermic reaction.
For example, 
In an exothermic reaction, energy of reactants is more than the energy of products.
This means that potential energy of products is less than the potential energy of reactants.
Thus, we can conclude that in the reaction
, the potential energy of the products is less than that of the reactant.
Answer:

Explanation:
Given that,
Mass, m = 27 grams
Volume of the substance, V = 15 cm³
We need to find the density of the substance. We know that, the density of an object is given by mass per unit volume. So,

So, the density of the substance is equal to
.