<span>This is because Helium
has two valence electrons compared to Hydrogen which has only one. Helium has
more energy levels for an electron to jump thus more spectral lines to occur.
The spectral lines relating to each change of energy level would be more
grouped together and hence the greater chance of them falling in the visible
range.</span>
Answer:
Heat flows from hot to cold objects. When a hot and a cold body are in thermal contact, they exchange heat energy until they reach thermal equilibrium, with the hot body cooling down and the cold body warming up. This is a natural phenomenon we experience all the time.
Explanation:
I know I'm a bit late but just in case you still need some of the answers.
1: Oxygen
2: Change in shape
3: Water breaking down into hydrogen and oxygen
4: I think it's Milk but I might be wrong.
I might be wrong about some of them, sorry it's not much.
Answer:
option E
Explanation:
given,
diameter = 4 mm
shutter speed = 1/1000 s
diameter of aperture = ?
shutter speed = 1/250 s
exposure time to the shutter time

N is the diameter of the aperture and t is the time of exposure
now,


inserting all the values

N₂² = 4
N₂ = 2 mm
hence , the correct answer is option E
Answer:
a) 32.58 m/s²
b) 161.84 m/s
Explanation:
Initial velocity = u = 0
Final velocity = v = 145 m/s
Time taken = t = 4.45 s
s = Displacement of dragster = 402 m
a = Acceleration


The final velocity is greater than the velocity used to find the average acceleration due to the gear changes. The first gear in a dragster has the most amount of toque which means the acceleration will be maximum. The final gears have less torque which means the acceleration is lower here. The final gears have less acceleration but can spin faster which makes the dragster able to reach higher speeds but slowly.