Answer: The threshold energy of the electrons in aluminium is 393.71 kJ/mol.
Explanation: Threshold energy is the minimum amount of energy which is required to emit a photon from a metal surface.
Mathematically,
Where,
E = Threshold energy
= Avogadro's constant = 
h = Planck's Constant = 
= Frequency of the particle =
Putting values in above equation, we get:
(Conversion Factor: 1kJ = 1000J)
Answer:
Explanation:
Force per unit length between two cables at distance d carrying current I₁ and I₂ can be given by the following expression .
F = 10⁻⁷ x 2I₁ I₂ / d
I₁ = I₂ = 15000 A
F = 10⁻⁷ x 2I₁ I₂ / d
= 10⁻⁷ x 2 x 15000² / 4.5 x 10⁻³ m
= 10000 N .
It will be repelling force ie they will repel each other because current is in opposite direction .
No , we should not be concerned about mechanical strength because force does not depend on it .
Answer:
F = F₀ 0.2
Explanation:
For this exercise we apply Coulomb's law with the initial data
F₀ = k q_A q_B / d²
indicate several changes
q_A ’= ½ q_A
q_B ’= 1/10 q_B
d ’= ½ d
let's substitute these new values in the Coulomb equation
F = k q_A ’q_B’ / d’²
F = k ½ q_A 1/10 q_B / (1/2 d)²
F = (k q_A q_B / d2) ½ 1/10 2²
F = F₀ 0.2
Answer:
mass of the object is : -
=》15.55 kg
Explanation:
force (f) = mass (M) × Acceleration (A)
=》280 = M × 18
=》M = 280 ÷ 18
=》M = 15.55 kg
<h3>Apparent magnitude of star:</h3>
Apparent magnitude of a star is how bright it appears on earth.
<h3>Absolute magnitude of star:</h3>
Absolute magnitude of star is how bright it appear from a distance of 32.6 light years from earth.
Due to farthest distance of star from earth, it appears smaller. But when we look at it from near it will appear greater in size or magnitude. That is why, we can say that absolute magnitude of some stars is greater than their apparent magnitude.
