Answer:
a) i = -9.63 cm
, h ’= .0.24075 cm erect
b) i = 259.74 cm
,
Explanation:
For this exercise let's start by finding the focal length of the lens
1 / f = (n-1) (1 / R₁ - 1 / R₂)
1 / f = (1.70 -1)) 1 / ∞ - 1/13)
1 / f = 0.0538
f = - 18.57 cm
Now we can use the constructor equation
1 / f = 1 / o + 1 / i
1 / i = 1 / f - 1 / o
1 / i = -1 / 18.57 -1/20
1 / i = -0.1038 cm
I = -9.63 cm
For the height of the
image let's use magnification
m = h '/ h = - i / o
h ’= -h i / o
h ’= - 0.5 (-9.63) / 20
h ’= .0.24075 cm
b) we invert the lens
The focal length is
1 / f = (1.70 -1) (1/13 - 1 / int)
1 / f = 0.0538
f = 18.57 cm
1 / i = 1 / f -1 / o
1 / I = 1 / 18.57 - 1/20
1 / I = 3.85 10-3
i = 259.74 cm
h ’= - 0.5 259.74 / 20
h ’= 6.4935 cm
Answer:
Explanation:
Power is related to energy by the following relationship:
where
P is the power used
E is the energy used
t is the time elapsed
In this problem, we know that
- the power of the fan is P = 120 W
- the fan has been running for one hour, which corresponds to a time of
So we can re-arrange the previous equation to find E, the energy (in the form of thermal energy) released by the fan:
Alpha particles travel through the air they collide with oxygen and nitrogen molecules. While they collide with these molecules, they lose some energy until all energy are used up and they are absorbed. These particles can be absorbed by a sheet of paper or by the air. On the other hand, beta particles and gamma particles move faster than the alpha particles and are poor at ionizing atoms or molecules thus it takes more of the material to be able to absorb these particles.
