Answer:
the crown was not made of pure gold
Explanation:
Mass of gold = weight in air/ g = 7.84N/10ms-2= 0.784 Kg or 0.8Kg
From Archimedes principle:
Upthrust= weight in air- weight in a fluid
Upthrust= volume × density × g
Note density of water = 1000kgm-3
7.84-6.84= V × 1000kgm-3×10ms-2
V= 1/10000= 1×10-4 m^3
Density = mass/ volume= 0.8/1×10-4
= 8×10^3 Kgm-3
But we know the density of gold to be 19.3 ×10^3 kgm-3
Hence the crown was not made of pure gold
Mirrors don't cause refraction.
A convex mirror could cause parallel rays to REFLECT away from each other.
Highest frequency EM waves: cosmic rays and gama rays
Lowest frequency EM waves:
Radio and Tv waves
Answer:
the total kinetic and potential energy of the ball is constant (mechanical energy remains the same)
Explanation:
As the ball falls, kinetic energy is increased in direct relation with the decrease in potential energy
ΔKE + ΔPE = 0
