Answer: The correct statements are ; A and B.
Explanation:
The strength of the magnetic field(B) in an electromagnet can be calculated using formula:
= Relative permeability
N = number of turns
I = Current in the wire of the solenoid
L = length of the solenoid or electromagnetic
As we can see from the formula:
So, by increasing the turns and increasing current flowing through wire one can increase the strength of an electromagnet.
Hence, the correct statements are ; A and B.
Answer: 4Kcal
Explanation:
H= mcø
M=200g
C= 1 cal/g/°c
Ø= 40-20=20°c
H= 200*1*20= 4000calories= 4Kcal
Answer:
The atomic number on the Periodic Table identifies the number of protons in any atom of that element. Copper, atomic number 29, has 29 protons. Finding the atomic number of an element reveals the number of protons.
To find the number of neutrons in the atom, subtract the atomic number from the atomic mass.
For radioactive decay, we can relate current amount, initial amount, decay constant and time using:
N = No x exp(-λt)
Half-life = ln(2)/λ
λ = ln(2) / 5730
N/No = 80% = 0.8
0.8 = exp( -ln(2)/5730 x t)
t = 1844 years
A) 120 mm
B) 127 mm
C) 914.4 mm
D) 1000 mm
E) 3048 mm
