' D ' is the only correct statement on the list.
Electromagnetic waves are capable of traveling through
many substances, and they're also capable of traveling
through vacuum. Mechanical waves can't travel in vacuum.
Answer: 
Explanation:
Given
Cross-sectional area of wire 
Extension of wire 
Extension in a wire is given by
where, 
for same force, length and material
Divide (i) and (ii)
Answer:
Sound travels through solids and liquids at the same speed
Explanation:
Because sound needs a dencer object to travel fast and since both liquid and solids are closer than gas sound travles faster in them.
