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A wave has wavelength 50 Å.
- Name the wave.
- State its speed in vacuum.
- State its one use.
Concept: Electromagnetic Spectrum
The smoke from a fire looks white. Which of the following statements is true?
1) Molecules of the smoke are bigger than the wavelength of light
2) Molecules of the smoke are smaller than the wavelength of light.
Concept: Colour in White Light with Their Wavelength and Frequency Range
To which regions of the electromagnetic spectrum do the following wavelengths belong:
(a) 250 nm
(b) 1500 nm
Concept: Electromagnetic Spectrum
Name two sources of ultraviolet radiation.
Concept: Electromagnetic Spectrum
A ray of light is incident at 45° on an equilateral prism in the diagram below.

- Name the phenomenon exhibited by the ray of light when it enters and emerges out of the prism.
- State the cause of the above phenomenon mentioned by you.
Concept: Dispersion of Light
Assertion (A): Ultraviolet radiations is scattered more as compared to the microwave radiations.
Reason (R): Wavelength of ultraviolet radiation is more than the wavelength of microwave radiation.
Concept: Electromagnetic Spectrum
Below is an incomplete table showing the arrangement of electromagnetic spectrum in the increasing order of their wavelength. Complete the table:
| Gamma ray | X - ray | UV rays | Visible rays | Infrared | A | Radio waves |
- Identify the radiation A.
- Name the radiation used to detect fracture in bones.
- Name one property common to both A and Radio waves.
Concept: Electromagnetic Spectrum
Name one radiation having the wavelength longer than the wavelength of these radiations.
Concept: Electromagnetic Spectrum
When sunlight passes through water droplets in the atmosphere it gets dispersed into its constituent colours forming a rainbow. A similar phenomenon is observed when white light passes through a prism.
Which colour will show the maximum angle of deviation and which colour will show the minimum angle of deviation?
Concept: Dispersion of Light
When sunlight passes through water droplets in the atmosphere it gets dispersed into its constituent colours forming a rainbow. A similar phenomenon is observed when white light passes through a prism.
Instead of sunlight, a green-coloured ray is passed through a glass prism. What will be the colour of the emergent ray?
Concept: Dispersion of Light
The human ear can detect continuous sounds in the frequency range from 20 Hz to 20,000 Hz. Assuming that the speed of sound in air is 330 ms1 for all frequencies; calculate the wavelengths corresponding to the given extreme frequencies of the audible range
Concept: Reflection of Sound Waves
An enemy plane is at a distance of 300 km from a radar. In how much time the radar will be able to detect the plane? Take velocity of radio waves as 3 x 108 ms-1
Concept: Characteristics of Sound
How is the frequency of a stretched string related to its length?
Concept: Reflection of Sound Waves
How is the frequency of a stretched string related it’s tension?
Concept: Reflection of Sound Waves
Name the factor that determines Loudness of the sound heard.
Concept: Characteristics of Sound
Name the factor that determines Quality of the note
Concept: Characteristics of Sound
Name the factor that determines Pitch of the note.
Concept: Characteristics of Sound
Name the phenomenon that causes a loud sound when the stem of a vibrating tuning fork is kept pressed on the surface of a table.
Concept: Characteristics of Sound
A wire of length 80 cm has a frequency of 256 Hz. Calculate the length of a similar wire under similar tension, which will have frequency 1024 Hz
Concept: Reflection of Sound Waves
