Answer:
1/2mv² = ke²
Explanation:
Let's suppose the material in question is a spring with spring constant k, mass m and position k, the kinetic energy possessed by the string will be;
K.E = 1/2mass×velocity² i.e 1/2mv²
Its elastic potential energy will be the work done on the spring when stretched which is equal to 1/2kx²
E.P = 1/2kx²
The equation describing the case where the kinetic energy is twice the elastic potential energy will be;
K.E = 2EP... 1)
Substituting the KE and EP formula into (1), we have;
1/2mv² = 2(1/2ke²)
1/2mv² = ke² which gives the required equation
Answer:
The specific gravity of the unkown liquid is 15.
Explanation:
Gauge pressure, at the bottom of the tank in this case, can be calculated from
where 
and 
are the height of the column of oil and the unkown liquid, respectively. Writing for 
, we have
Relative to water, the unknow liquid specific weight is 15 times bigger, therefore this is its specific gravity as well.
Answer:
Explanation:
Threshold frequency = 4.17 x 10¹⁴ Hz .
minimum energy required = hν where h is plank's constant and ν is frequency .
E = 6.6 x 10⁻³⁴ x 4.17 x 10¹⁴
= 27.52 x 10⁻²⁰ J .
wavelength of radiation falling = 245 x 10⁻⁹ m
Energy of this radiation = hc / λ
c is velocity of light and λ is wavelength of radiation .
= 6.6 x 10⁻³⁴ x 3 x 10⁸ / 245 x 10⁻⁹
= .08081 x 10⁻¹⁷ J
= 80.81 x 10⁻²⁰ J
kinetic energy of electrons ejected = energy of falling radiation - threshold energy
= 80.81 x 10⁻²⁰ - 27.52 x 10⁻²⁰
= 53.29 x 10⁻²⁰ J .
Answer:
Choice A.
Nearness to a body of water causes an increase in humidity, due to the higher rate of evaporation.
