1. The answer is
"a".<span>
Mechanical waves require a medium to travel. If there is no
medium, the mechanical wave doesn't travel. Since, they are waves; they have a
wavelength, frequency, speed and
also amplitude. The speed depends on the medium and type of the wave. An example
for the mechanical waves is sound wave.</span>
<span>2. E = hf, where E is energy, h is plank constant and f is the frequency. Hence, if the frequency is high, then the energy is high. </span>
v = fλ , where v is the speed, f is the frequency and λ is the wavelength. If the frequency is high, then the wavelength is low.
According to the given choices, gamma rays have the shortest wavelength and highest energy on electromagnetic spectrum.
3. The wavelength
of X-rays are smaller the wavelength of infrared.
<span>According to the
v=fλ, lower the wavelength, then higher the frequency. According to the E = hf, if the frequency
is high, then the energy is also high. </span>
Hence, the correct
answer is "d"
4. <span>In a
longitudinal wave (compression wave) the
particles of a matter move </span>parallel.
There are two types
of waves according to the particle movement. They are transverse waves and
longitudinal waves. In transverse waves, the particles of the medium move
perpendicular to the direction of the wave and longitudinal waves have
parallel movement of particles to the direction of wave.
5. In regard
to spend of sound, sound travels slowest in gases.
<span>Solids have the
highest speed of sound while gases have the lowest. This is because of the
particle arrangement of each phase. Solid phase has very tightly packed particle
arrangement and due to that the transfer of sound wave in easy than in gases.</span>
