Waves Test

Result

Waves Test - 25

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Two small boats are $$10m$$ apart on a lake. Each pops up and down with a period of $$4.0\ \text{seconds}$$ due to wave motion on the surface of the water. When one boat is at its highest point, the other boat is at its lowest point. Both boats are always within a single cycle of the waves. The speed of the waves is

A
$$2.5\ \text{m/s}$$

B
$$5.0\ \text{m/s}$$

C
$$14\ \text{m/s}$$

D
$$40\ \text{m/s}$$

Solution

$$\dfrac{\lambda}{2}=10\ \text{m}\Rightarrow \lambda=20\ \text{m}$$

$$\text{Time period}= T=4\ \text{sec}$$

$$ V=\dfrac{\lambda}{T}=\dfrac{20}{4}=5\ \text{m/s}$$
Question 2
1 / -0

If the frequency of a wave is increased by 25 %, then the change in its wavelength will be:
(medium not changed)

A
20 % increase

B
20 % decrease

C
25 % increase

D
25 % decrease

Solution

Since, the medium has not changed, speed of wave remains
same.
$$v=\nu_1 \lambda_1=\nu_2 \lambda_2$$
$$\nu_2=1.25 \nu_1$$
$$\lambda_2=\dfrac{\nu_1}{\nu_2} \lambda_1=\dfrac{1}{1.25} \lambda_1=(4/5) \lambda_1$$
$$ \dfrac {\Delta \lambda}{\lambda _1} = \dfrac{\lambda_2- \lambda_1}{\lambda_1} \times 100= \dfrac{(4/5)\lambda_1- \lambda_1}{\lambda_1} \times 100=-(1/5)\times 100=-20$$ %
option "B" is correct.
Question 3
1 / -0

An object is vibrating at $$50$$ hertz. What is its time period?

A
$$0.02$$ s

B
$$0.2$$ s

C
$$2$$ s

D
$$20.0$$ s

Solution

From the definition of frequency $$\nu= \dfrac{1}{T}$$

and we are given $$\nu=50 hertz $$.

Substituting, we have $$50 = \dfrac{1}{T}$$ or

$$T = 0.02 s$$
Question 4
1 / -0

The frequency of a man's voice is 300 Hz and its wavelength is 1 meter. If the wavelength of a child's voice is 1.5 m, then the frequency of the child's voice is :

A
200 Hz

B
150 Hz

C
100 Hz

D
350 Hz.

Solution

$$\nu_1\lambda_1= \nu_1\lambda_1$$ since $$v= \nu\lambda$$ is same for both a man and child.

$$ \therefore 300 \times 1 = \nu_2 \times 1.5$$

$$ \Rightarrow \nu_2 = 200 \: Hz$$
Question 5
1 / -0

Sound waves are .................... waves.

A
Transverse

B
Longitudinal

C
Straight Line

D
None of these

Solution

Sound waves are called longitudinal waves because sound requires a material medium for their propagation.
Hence, the correct option is B
Question 6
1 / -0

Frequency of the sinusoidal wave, y = 0.40 cos (2000t + 0.080) would be :

A
100 at Hz

B
2000 Hz

C
20 Hz

D
318Hz

Solution

The general form of a sinusoidal wave is,
$$y=A cos(2\pi\nu t+\phi)$$, where,
$$A=$$amplitude of the wave
$$\nu= $$frequency
$$\phi=$$phase shift
Comparing this with the given equation then the frequency will comes out to be,
$$\omega = 2\pi f $$
Here $$\omega = 2000$$ Therefore will get frequency as,
$$\omega = 2\pi f = 2000$$
Calculating,
$$f=318\ Hz$$
Question 7
1 / -0

The frequency of sound waves is 11 kHz and its wavelength is 20 cm, then the velocity of sound waves is :

A
220 m s$$^{-1}$$

B
220 cm s$$^{-1}$$

C
2200 cm s$$^{-1}$$

D
2200 m s$$^{-1}$$

Solution

Velocity of sound wave $$V=n \lambda$$ i.e. the product of the frequency and amplitude of the wave.

So, $$V=11 \times 10^3 \times 20 \times 10^{-2}=2200$$ m/s
Question 8
1 / -0

The type of waves is/ are

A
Progressive

B
Stationary

C
Both (a) and (b)

D
None of these

Solution
Question 9
1 / -0

If the vibration of particles in a wave is perpendicular to the direction of propagation of wave, then it is called,

A
Transverse waves

B
Reflective waves

C
Incident waves

D
None of these

Solution
Question 10
1 / -0

Elastic waves in solid are :

A
Transverse Only

B
Longitudinal Only

C
Either transverse or longitudinal

D
Neither transverse nor longitudinal

Solution

Elastic wave, motion in a medium in which, when particles are displaced, a force proportional to the displacement acts on the particles to restore them to their original position. so depending on the forces acting the waves may be either longitudinal or transverse .
the answer is C.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Waves Test - 25

Result

Waves Test - 25

Score

-

Rank

-

SHARING IS CARING

Question 1

$$2.5\ \text{m/s}$$

$$5.0\ \text{m/s}$$

$$14\ \text{m/s}$$

$$40\ \text{m/s}$$

Solution

Question 2

20 % increase

20 % decrease

25 % increase

25 % decrease

Solution

Question 3

$$0.02$$ s

$$0.2$$ s

$$2$$ s

$$20.0$$ s

Solution

Question 4

200 Hz

150 Hz

100 Hz

350 Hz.

Solution

Question 5

Transverse

Longitudinal

Straight Line

None of these

Solution

Question 6

100 at Hz

2000 Hz

20 Hz

318Hz

Solution

Question 7

220 m s$$^{-1}$$

220 cm s$$^{-1}$$

2200 cm s$$^{-1}$$

2200 m s$$^{-1}$$

Solution

Question 8

Progressive

Stationary

Both (a) and (b)

None of these

Solution

Question 9

Transverse waves

Reflective waves

Incident waves

None of these

Solution

Question 10

Transverse Only

Longitudinal Only

Either transverse or longitudinal

Neither transverse nor longitudinal

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.