True because , a compound forms when two or more atoms form a chemical bond and the chemical formula for water is H2O which means each molecule of water consists of one oxygen atom
True if you look up the question Is velocity speed in a certain direction you would’ve gotten the answer but I’m pretty sure it’s true
Answer:
They have a dual wave-particle nature.
Explanation:
Electromagnetic waves consist of periodic oscillations of electric and magnetic field in a plane perpendicular to the direction of motion of the wave (in fact, they are also classified as transverse waves).
Electromagnetic waves have a wave nature, however they also have particle nature - in fact, it has been proved in some experiment (e.g. photoelectric effect) that in some conditions they act as packets of particles - called photons. Therefore, the option
They have a dual wave-particle nature.
is correct.
Other options are wrong because:
They are all invisible. --> False because visible light (which is part of the electromagnetic spectrum, so they are electromagnetic waves) is visible
They can only travel without a medium. --> False because they can also travel in a vacuum
They are slower than sound waves. --> False because they travel much faster (they travel at the speed of light in a vacuum,
, while sound travels at 343 m/s in air, for instance)
Answer:
Explanation:
Work done in lifting the weight once = mgh
= 20 x 9.8 x (1.9+1.7)
= 705.6 J
= 705.6 / 4.2 calorie
= 168 cals
Total energy to be spent = 600 x 10³ cals
No of times weight is required to be lifted
= 600 x 10³ / 168
= 3.57 x 10³ times
Total time to be taken = 2 x 3.57 x 10³
= 7.14 x 10³ s
=119 minutes .
Hello!
First one we can use that PE=mgh so we have
4.37*10^5J/(9.12*10^3kg*9.80m/s^2)= 4.89m
Second one we can use Newton’s Second Law
F=ma and in this case F=mg so we have
g= 3.28*10^-2N/6*10^-3kg = 5.47m/s^2
Hope this helps. Any questions please ask. Thank you.