Answer:
6.8 mm
Explanation:
We are given that
Mass of block,m=10 kg
Mass of bullet,
1 kg=1000 g
Total mass of system,M=
Speed of bullet,u=300 m/s

By law of conservation of momentum


According to law of conservation of energy
Change in kinetic energy of system=Change in potential energy of system


Where 

1m=100 cm

Distance traveled by block=
1cm=10 mm
.Answer:
491.4 nm
Explanation:
The distance between central and first maxima is,

And the distance between screen abnd grating is,

Now the angle can be find as,

Now the grating distance is,

Now with m=1 condition will become,

So,

Therefore the wavelength of laser light is 491.4 nm.
Answer: Sorry the pic is too blurry try making the resolution higher
Answer:
a) the Tunguska meteoric impact
Explanation:
The Tunguska Event, sometimes known as the Tungus Meteorite is thought to have resulted from an asteroid or comet entering the earth's atmosphere and exploding. The event released as much energy as fifteen one-megaton atomic bombs. As well as blasting an enormous amount of dust into the atmosphere, felling 60 million trees over an area of more than 2000 square kilometres. Shaidurov suggests that this explosion would have caused "considerable stirring of the high layers of atmosphere and change its structure." Such meteoric disruption was the trigger for the subsequent rise in global temperatures
According to Vladimir Shaidurov of the Russian Academy of Sciences, the apparent rise in average global temperature recorded by scientists over the last hundred years or so could be due to atmospheric changes that are not connected to human emissions of carbon dioxide from the burning of natural gas and oil.