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2 years ago

Find the wavelength of the ultrasonic wave emitted by a bat if it has a frequency of 4.0 * 10^4 Hz.

Physics

2 answers:

Oliga [24]2 years ago

6 0

ultrasonic wave is a type of sound wave. speed of sound in air at room temp is 343m/s.

speed = wavelength * frequency

wavelength = speed / frequency = 343/4*10^4

= 0.00858m

= 8.58mm

morpeh [17]2 years ago

5 0

Remark

You have to pick a velocity for an ultra sound wave. I'm going to take the sound velocity to be 331 m/s in air, because I'm assuming that is what is meant: it is the sound a bat would make once he emits the ultrasound to a microphone like device that receives it. The media through which that happens is air.

Givens

v = 331m/s

f = 4 *10^4 hz

Formula

velocity = wavelength * frequency

v = $\lambda$ *f

331/(4*10^4) = $\lambda$

0.008275 = $\lambda$

8.275*10^-3 = $\lambda$

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A Carnot heat engine uses a hot reservoir consisting of a large amount of boiling water and a cold reservoir consisting of a lar

horrorfan [7]

Answer:

W= 4.89 KJ

Explanation:

Lets take

temperature of hot water T₁ = 100⁰C

T₁ = 373 K

Temperature of cold ice T₂= 0⁰C

T₂ = 273 K

The latent heat of ice LH= 334 KJ

The heat rejected by the engine Q= m .LH

Q₂= 0.04 x 334

Q₂= 13.36 KJ

Heat gain by engine = Q₁

For Carnot engine

$Q_1=\dfrac{T_1}{T_2}Q_2$

$Q_1=\dfrac{373}{273}\times 13.36$

Q₁ = 18.25 KJ

The work W= Q₁ - Q₂

W= 18.25 - 13.36 KJ

W= 4.89 KJ

7 0

2 years ago

Read 2 more answers

Convert the following as instructed:

Elis [28]

3.4m
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172800s
1 day

7 0

2 years ago

Find the voltage change when: a. An electric field does 12 J of work on a 0.0001-C charge. b. The same electric field does 24 J

kondaur [170]

Explanation:

Given that,

(a) Work done by the electric field is 12 J on a 0.0001 C of charge. The electric potential is defined as the work done per unit charged particles. It is given by :

$V=\dfrac{W}{q}$

$V=\dfrac{12}{0.0001}$

$V=12\times 10^4\ Volt$

(b) Similarly, same electric field does 24 J of work on a 0.0002-C charge. The electric potential difference is given by :

$V=\dfrac{W}{q}$

$V=\dfrac{24}{0.0002}$

$V=12\times 10^4\ Volt$

Therefore, this is the required solution.

7 0

2 years ago

two resistors of resistance 6 ohm and 3 ohm are connected in series and then in parallel .calculate the equivalent series resist

Novosadov [1.4K]

Explanation:

Given that,

Two resistors of resistance 6 ohm and 3 ohm are connected in series and then in parallel.

For series combination,

$R_{eq}=R_1+R_2$

For parallel combination,

$\dfrac{1}{R_{eq}}=\dfrac{1}{R_1}+\dfrac{1}{R_2}$

When 6 ohm and 3 ohm are in series,

$R_s=6+3\\\\R_s=9\ \Omega$

When 6 ohm and 3 ohm are in paralle,

$\dfrac{1}{R_p}=\dfrac{1}{6}+\dfrac{1}{3}\\\\R_p=2\ \Omega$

So, the equivalent resistance in series combination is 9 ohms and in parallel combination it is 2 ohms.

6 0

2 years ago

a 5.0 kg ball is dropped from a 2.5 m high window. what is the velocity of the ball just before it hits the ground?

julsineya [31]

Answer:

Approximately $7.0\; \rm m \cdot s^{-1}$ .

Assumption: the ball dropped with no initial velocity, and that the air resistance on this ball is negligible.

Explanation:

Assume the air resistance on the ball is negligible. Because of gravity, the ball should accelerate downwards at a constant $g = 9.81 \; \rm m \cdot s^{-2}$ near the surface of the earth.

For an object that is accelerating constantly,

$v^2 - u^2 = 2\, a \, x$ ,

where

$u$ is the initial velocity of the object,
$v$ is the final velocity of the object.
$a$ is its acceleration, and
$x$ is its displacement.

In this case, $x$ is the same as the change in the ball's height: $x = 2.5\; \rm m$ . By assumption, this ball was dropped with no initial velocity. As a result, $u = 0$ . Since the ball is accelerating due to gravity, $a = 9.81\; \rm m \cdot s^{-2}$ .

$v^2 - u^2 = 2\, g \cdot h$ .

In this case, $v$ would be the velocity of the ball just before it hits the ground. Solve for

$v^2 = 2\, a\, x + u^2$ .

$\begin{aligned}v &= \sqrt{2\, a\, x + u^2} \\ &= \sqrt{2\times 9.81 \times 2.5 + 0} \\ &\approx 7.0\; \rm m\cdot s^{-1}\end{aligned}$ .

3 0

2 years ago