1. Astronomical observatories have been available since ancient times, and many cultures set aside special sites for astronomica
1 answer:
You might be interested in
Answer:
<em> B) The voltage on dry skin needs to be 200 times larger than the voltage on wet skin.</em>
<em></em>
Explanation:
This is the complete question
A person will feel a shock when a current of greater than approximately 100μ A flows between his index finger and thumb. If the resistance of dry skin is 200 times larger than the resistance of wet skin, how do the maximum voltages without shock compare in each scenario?
A) The voltage on dry skin needs to be 200 times smaller than the voltage on wet skin.
B) The voltage on dry skin needs to be 200 times larger than the voltage on wet skin.
C) The voltage on dry skin is the same as the voltage on wet skin.
D) The voltage on dry skin needs to be 40,000 times larger than the voltage on wet skin.
Ohm's law states that electric current is proportional to voltage and inversely proportional to resistance.
the equation is written as
V = IR
Where V is the voltage
I is the current
R is the resistance
for this case, the current I is 100μ A = 100 x 10^16 A
resistance of wet skin = R
resistance of dry skin = 200R
for the wet skin, voltage will be
V = IR =
for dry skin, voltage will be
V = IR =
Comparing both voltages
÷
= 200
<em>this means that the voltage on the wet skin should be 200 times lesser than the voltage on the dry skin or the voltage on the dry skin should be 200 times more than the voltage on the wet skin.</em>
Answer:
- <u><em>(b) 1:1</em></u>
Explanation:
<u></u>
<u>1. Formulae:</u>
- E = hf
- E = h.v/λ
- λ = h/(mv)
- E = (1/2)mv²
Where:
- E = kinetic energy of the particle
- λ = de-Broglie wavelength
- m = mass of the particle
- v = speed of the particle
- h = Planck constant
<u><em>2. Reasoning</em></u>
An alha particle contains 2 neutrons and 2 protons, thus its mass number is 4.
A proton has mass number 1.
Thus, the relative masses of an alpha particle and a proton are:
For the kinetic energies you find:
Thus:
From de-Broglie equation, λ = h/(mv)