Answer:
Option B. 32 g
Explanation:
From the question given above, the following data were obtained:
Original amount (N₀) = 128 g
Half-life (t½) = 2.25 billion years
Number of half-lives (n) = 2
Amount remaining (N) =?
The amount of 128 gram of Radium-226 that will remain after 2 half-lives has elapsed can be obtained as followb
N = 1/2ⁿ × N₀
N = 1/2² × 128
N = 1/4 × 128
N = 0.25 × 128
N = 32 g
Therefore, 32g of the sample will remain.
FOUR USES OF CONCAVE MIRROR:Satellite dishes,headlights of a car, telescopes used for astronomical studies, and shaving mirrors because of there curved and reflective surface.
FIVE USES OF LENSES: Camera lens ,microscopes ,magnifying glass,eyeglasses,projector
Answer:
13.51 nm
Explanation:
To solve this problem, we are going to use angle approximation that sin θ ≈ tan θ ≈ θ where our θ is in radians
y/L=tan θ ≈ θ
and ∆θ ≈∆y/L
Where ∆y= wavelength distance= 2.92 mm =0.00292m
L=screen distance= 2.40 m
=0.00292m/2.40m
=0.001217 rad
The grating spacing is d = (90000 lines/m)^−1
=1.11 × 10−5 m.
the small-angle
approx. Using difraction formula with m = 1 gives:
mλ = d sin θ ≈ dθ →
∆λ ≈ d∆θ = =1.11 × 10^-5 m×0.001217 rad
=0.000000001351m
= 13.51 nm
Answer:
A.
Explanation:
an atom that has most of its mass is electrons.
