Answer:
Explanation:
we know that half life of an element is
T=0.693/λ
where λ is decay constant in order to find decay constant
λ=0.693/T
λ=0.693/8.04
λ=0.086
Answer:
(A) the angular acceleration of the blades is 13.33 m/s.
Explanation:
Given;
moment of inertia of a blade, I = 0.2 kgm²
net torque exerted on fan blades, ∑τ = 8Nm
Torque is given as product of moment of inertia and angular acceleration;
τ = Iα
where;
α is the angular acceleration
Since there are three blades of the ceiling fan, the net torque is given as;
∑τ = (3I)α
∑τ = 3Iα
α = ∑τ / 3I
α = (8) / (3 x 0.2)
α = 13.33 m/s
Therefore, the angular acceleration of the blades is 13.33 m/s.
The electron is accelerated through a potential difference of

, so the kinetic energy gained by the electron is equal to its variation of electrical potential energy:

where
m is the electron mass
v is the final speed of the electron
e is the electron charge

is the potential difference
Re-arranging this equation, we can find the speed of the electron before entering the magnetic field:

Now the electron enters the magnetic field. The Lorentz force provides the centripetal force that keeps the electron in circular orbit:

where B is the intensity of the magnetic field and r is the orbital radius. Since the radius is r=25 cm=0.25 m, we can re-arrange this equation to find B:
It’s frequency is high and microwaves can pass through the atmosphere of the Earth.