Answer:
51 mph
Explanation:
Given: A certain aircraft can fly 612 miles with the wind in 3 hours and travel the same distance against the wind in 6 hours.
Formula: 
Let speed of aircraft be x mph and speed of wind y mph
Aircraft along wind:
Actual speed of aircraft = x + y
Time taken = 3 hours
Distance = 612 miles
Aircraft against wind:
Actual speed of aircraft = x - y
Time taken = 6 hours
Distance = 612 miles
By solving equation (1) and equation (2) and we get
x = 153 mph
y = 51 mph
Hence, The speed of wind will be 51 mph
Answer:
This represents radiation in ultra-violet region .
Explanation:
Energy of the orbit where n = 3 is given as follows
= -1.511 eV
Energy of the orbit where n = 1 is given as follows
= 13.6 eV
Difference of [tex]E_3 and [tex]E_1 = - 1.511+ 13.6
= 12.089 eV.
The wavelength of light having this energy in nm is given by the expression as follows
Wavelength in nm = 1244 / energy in eV
= 1244 / 12.089
= 102.90 nm
This represents radiation in ultra-violet region .
All of these things were seen in formal experiments by the 19th century. But some of them are easy to see in your own home. It's obvious that light can reflect - you just have to look in a mirror. Light bounces off the mirror and goes into your eye so you can see yourself. It's also obvious that light can refract: All you have to do is put a spoon in a large glass of water and watch how the spoon appears to bend.
That happens because the light is bending as it moves between air and water. Both of these things can be seen even more clearly in a laboratory using beams of light or lasers.
Answer:
Explanation:
The force that one atom exerts on the other is the negative derivative of the potential energy = 
F(x) = - 
( -C₆ / x⁷) = - (- (-6) C₆ x⁻⁶ ⁻¹) = - 6C₆ /x⁷
when xis negative, F is positive and when x is positive, F is negative. It is therefore and attractive force and F is always directed to the center
