The correct answer is letter D. candela. The unit for measuring the rate at which light energy is radiated from a source is the candela. L<span>umen is the unit for measuring the total amount of visible light emitted by a source. Lux is lumen per square meter. </span>
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Answer:
Explanation:
given
T = 3months = 7.9 × 10⁶s
orbital speed = 88 × 10³m/s
V= 2πr÷T
∴ r = (V×T) ÷ 2π
r = (88km × 7.9 × 10⁶s) ÷ 2π
r = 1.10 × 10⁸km
using kepler's 3rd law
mass of both stars = (seperation diatance)³/(orbital speed)²
M₁ + M₂ = (2r)³/(
year)²
= (1.06 × 10²⁵)/(6.2×10¹³)
1.71×10¹²kg
since M₁ = M₂ =1.71×10¹²kg ÷ 2
M₁ = M₂ = 8.55×10¹¹kg
Answer:
7.78 * 10³ m/s
Explanation:
Orbital velocity is given as:
v = √(GM/R)
G = 6.67 * 10^(-11) Nm/kg²
M = 5.98 * 10^(24) kg
R = radius of earth + distance of the satellite from the surface of the earth
R = 2.15 * 10^(5) + 6.38 * 10^(6)
R = 6.595 * 10^(6) m
v = √([6.67 * 10^(-11) * 5.98 * 10^(24)] / 6.595 * 10^(6))
v = √(6.048 * 10^7)
v = 7.78 * 10³ m/s
