Advertisements
Advertisements
प्रश्न
A SONAR (sound navigation and ranging) uses ultrasonic waves to detect and locate objects under water. In a submarine equipped with a SONAR the time delay between generation of a probe wave and the reception of its echo after reflection from an enemy submarine is found to be 77.0 s. What is the distance of the enemy submarine? (Speed of sound in water = 1450 m s–1).
Advertisements
उत्तर १
Let the distance between the ship and the enemy submarine be ‘S’.
Speed of sound in water = 1450 m/s
Time lag between transmission and reception of Sonar waves = 77 s
In this time lag, sound waves travel a distance which is twice the distance between the ship and the submarine (2S).
Time taken for the sound to reach the submarine = `1/2 xx 77 = 38.5 s`
∴ Distance between the ship and the submarine (S) = 1450 × 38.5 = 55825 m = 55.8 km
उत्तर २
Here speed of sound in water v = 1450 m s-1and time of echo t = 77.0 s.
If distance of enemy submarine be d, then t = 2d/v
∴ d=vt/2 =1450 x 77.0/2 =55825 m=55.8 x 103 m or 55.8 km
संबंधित प्रश्न
Round up the following upto three significant figures:
10.4107
Round up the following upto three significant figures:
2808
How many significant figures should be present in the answer of the following calculation:-
`(0.02856 xx 298.15 xx 0.112)/0.5785`
How many significant figures should be present in the answer of the following calculation?
0.0125 + 0.7864 + 0.0215
The relative density of lead is 11.3. Its density is ______ g cm–3or ______ kg m–3.
The length, breadth, and thickness of a rectangular sheet of metal are 4.234 m, 1.005 m, and 2.01 cm respectively. Give the area and volume of the sheet to correct significant figures.
It is a well known fact that during a total solar eclipse the disk of the moon almost completely covers the disk of the Sun. From this fact and from the information you can gather from examples 2.3 and 2.4, determine the approximate diameter of the moon.
State the number of significant figures in the following:
6.320 J
State the number of significant figures in the following:
0.0006032 m2
A large ball 2 m in radius is made up of a rope of square cross-section with edge length 4 mm. Neglecting the air gaps in the ball, what is the total length of the rope to the nearest order of magnitude?
Solve the numerical example.
Nuclear radius R has a dependence on the mass number (A) as R =1.3 × 10-16 A1/3 m. For a nucleus of mass number A = 125, obtain the order of magnitude of R expressed in the meter.
Solve the numerical example.
The diameter of a sphere is 2.14 cm. Calculate the volume of the sphere to the correct number of significant figures.
How many significant figures should be present in the answer of the following calculations?
`(2.5 xx 1.25 xx 3.5)/2.01`
The number of significant figures in 0.06900 is ______.
The sum of the numbers 436.32, 227.2 and 0.301 in appropriate significant figures is ______.
Why do we have different units for the same physical quantity?
How many significant figures are present in the measurement 2007 grams?
How many significant figures are there in the number 0.001405?
The radius of Earth is expressed as 0.64 × 10⁷ m in scientific notation. What is its order of magnitude and number of significant figures?
