Answer: 3.
Explanation:
The correct answer is a higher amplitude and lower frequency. Since an opera singer is lowering his pitch it means that he is creating higher amplitude and because he is raising his voice for a song with that higher amplitude he is creating lower frequency.









☯ <u>Using 1st equation of motion </u>











☯ <u>Now, Finding the force exerted </u>







☯ <u>Hence</u>, 

NO musical instrument produces a 'pure' tone with only a
single frequency in it.
EVERY instrument produces more or less harmonics (multiples)
in addition to the basic frequency it's playing.
The percussion instruments (drums etc) are the richest producers
of bunches of different frequencies.
Fuzzy electric guitars are next richest.
The strings and brass instruments are moderate producers of
harmonics ... I can't remember which is greater than the other.
Then come the woodwinds ... clarinet, oboe, etc.
The closest to 'pure' tones of single frequency are the sounds
made by the flute and piccolo, but even these are far from 'pure'.
The only way to get a true single-frequency sound is from an
electronic 'sine wave' generator.
Answer:
145 m
Explanation:
Given:
Wavelength (λ) = 2.9 m
we know,
c = f × λ
where,
c = speed of light ; 3.0 x 10⁸ m/s
f = frequency
thus,

substituting the values in the equation we get,

f = 1.03 x 10⁸Hz
Now,
The time period (T) = 
or
T =
= 9.6 x 10⁻⁹ seconds
thus,
the time interval of one pulse = 100T = 9.6 x 10⁻⁷ s
Time between pulses = (100T×10) = 9.6 x 10⁻⁶ s
Now,
For radar to detect the object the pulse must hit the object and come back to the detector.
Hence, the shortest distance will be half the distance travelled by the pulse back and forth.
Distance = speed × time = 3 x 10^8 m/s × 9.6 x 10⁻⁷ s) = 290 m {Back and forth}
Thus, the minimum distance to target =
= 145 m