Explanation:
(a) First, we will calculate the number of moles as follows.
No. of moles = 
Molar mass of helium is 4 g/mol and mass is given as 0.1 kg or 100 g (as 1 kg = 1000 g).
Putting the given values into the above formula as follows.
No. of moles = 
=
= 25 mol
According to the ideal gas equation,
PV = nRT
or, 

= 336.17 K
Hence, temperature change will be 336.17 K.
(b) The total amount of heat required for this process will be calculated as follows.
q = 
= 
= 174573.081 J/K
or, = 174.57 kJ/K (as 1 kJ = 1000 J)
Therefore, the amount of total heat required is 174.57 kJ/K.
Answer:
A= 61.35
B= -44.40
Explanation:
1. Using the components method we have:

Considering that the vector sum
, then:

Then:

It means the value of x and y component is 0.
2. Determinate the equations that describe each component:

Form Eq. (1):

Replacing A in Eq. (2):

Replacing values of C, α and β in (4):

Replacing value of B in (3)

The resistance of a conductor is given by

where L is the length of the wire,

the resistivity of the material and A the cross-sectional area.
We can see that if all the other quantities do not change, if the new length of the conductor is 4 times the original length:

, then the new resistance is also 4 times the original value:
Answer:
Explanation:
The energy of a photon is given by the equation
, where h is the <em>Planck constant</em> and f the frequency of the photon. Thus, N photons of frequency f will give an energy of
.
We also know that frequency and wavelength are related by
, so we have
, where c is the <em>speed of light</em>.
We will want the number of photons, so we can write

We need to know then how much energy do we have to calculate N. The equation of power is
, so for the power we have and considering 1 second we can calculate the total energy, and then only consider the 4% of it which will produce light, or better said, the N photons, which means it will be
.
Putting this paragraph in equations:
.
And then we can substitute everything in our equation for number of photons, in S.I. and getting the values of constants from tables:
