When light crosses the interface between a medium with higher refractive index and a medium with lower refractive index, there is a maximum value of the angle of incidence after which there is no refraction, but all the light is reflected, and this maximum value is called critical angle.
The critical angle is given by

where n1 is the refractive index of the first medium while n2 is the refractive index of the second medium. In our problem, n1=1.33 and n2=1.58, so the critical angle is
Answer:
a)Change in the speed = 1.41 m/s
b)The final speed will be 3.11 m/s
Explanation:
Given that
Acceleration ,a= 4.7 x 10⁻³ m/s²
a)
We know that
v= u + a t
v=final speed ,u=initial speed
t= time ,a= acceleration
Change in the speed
v- u = a t
t= 5 min = 5 x 60 s = 300 s
v- u = 4.7 x 10⁻³ x 5 x 60 m/s
v-u = 1.41 m/s
Change in the speed = 1.41 m/s
b)
Given that
u= 1.7 m/s
v-u = 1.41 m/s
v= 1.7 + 1.41 m/s
v=3.11 m/s
The final speed will be 3.11 m/s
You must know the concept of pH of a solution and its relation to the concentration of H+ and OH- ions. pH is a measure of the substance's acidity or basicity. From the definition of Arrhenius, an acid contains an H+ while a base contains a OH- ion. From this definition, we can say that an acidic substance has a higher concentration of H+ ions. Now, I'll introduce here that pH is the value of the negative logarithm of the concentration of H+. In equation,
pH = -log[H+]
The term pOH is therefore also, pOH = -log[OH-]. Therefore, the relationship that connects the two negative logarithms is:
pH + pOH = 14
The pH scale starts from 1 being the most acidic to 14 being the most basic. The neutral pH is 7. Thus, for a pH of 7, the H+ and the OH- concentrations are equal.
pH = 7 = -log[H+][H+] = 1×10⁻⁷ mol/L = [OH-]
Since the concentrations are equal, the ratio is equal to 1.
<span>Energy is transferred from one object to another
when a reaction takes place. Energy comes in many forms and can be
transferred from one object to another as heat, light, or motion, to
name a few. For the blue ball to move to the position of the green ball,
energy must be given to the blue ball. This energy would be in the form
of motion, with the person lifting the blue ball to a higher level.
This form of energy is called kinetic energy.</span>