81. How much should minimum distance be between the source of sound and reflecting surface, so that an echo can be heard clearly?

1. 10 meter
2. 17 meter
3. 24 meter
4. 30 meter

Option “2” is correct.
The repetition of sound produced due to the reflection from a large surface like wall, hill or mountain is called echo. Minimum distance between source of sound and reflecting surface be 17 meter so that an echo can be heard.
82. Consider the following statements about ultrasonic waves:

1. They can destroy insects.
2. They can clean clothes by removing dust.
3. They can be used to treat diseases.
4. They can control automatic doors.
Of the above statements

1. 1 and 2 are correct
2. 3 and 4 are correct
3. 1, 2 and 3 are correct
4. All are correct

Option “4” is correct.
Sound waves are divided into three categories that cover different frequency range; Audible waves (20 Hz- 20,000 Hz), Infrasonic waves (<20 Hz) and Ultrasonic waves (>20,000 Hz). Ultrasonic waves are used to destroy insects, clean clothes by removing dust, treat diseases, control automatic doors, detection of aircraft and submarine, determination of depth of sea etc.
83. What is the SI unit of intensity of sound?

1. Decibel
2. Newton
3. Hertz
4. Tesla

Option “1” is correct.
Decibel(dB) is the SI unit of intensity of sound.
84. Which colour is formed when Blue and Green are mixed?

1. Cyan
2. Brown
3. Black
4. Violet

Option “1” is correct.
When blue and green colour combine, the result is cyan.
85. What is the SI unit of Power?

1. Boyle
2. Watt
3. Newton
4. Pascal

Option “2” is correct.
SI unit of power is watts. A watt is the power that it takes to do one joule of work in one second.
86. The gas used in discharge tubes for optical decoration and advertising is-

1. Carbon dioxide
2. Ammonia
3. Sulphur dioxide
4. Neon

Option “4” is correct.
The neon gas is used in discharge lamps, tubes and in fluorescent bulbs.
87. The distance-time graph for the motion of an object moving with a constant speed is a __________.

1. Dot
2. Circle
3. Straight Line
4. Curve

Option “3” is correct.
The distance-time graph for the motion of an object moving with a constant speed is a Straight Line.
88. If the force applied on the object is in the direction of its motion, the speed of the object __________.

1. Increases
2. Stops
3. Decreases
4. No effect

Option “1” is correct.
If the force applied on the object is in the direction of its motion, the speed of the object increases.
89. Sphygmomanometer measures the blood pressure in the-

1. Veins
2. Arteries
3. Eyes
4. Synovial

Option “2” is correct.
Blood pressure is measured by instrument called sphygmomanometer also called as blood pressure meter, it is used to measure the pressure of blood in Arteries.
90. The reverse effect of X-ray emission is-

1. Raman effect
2. Compton effect
3. Zeeman effect
4. Photo-electric effect

Option “4” is correct.
The reverse effect of X-ray emission is Photo-electric effect.
Pages: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

17 thoughts on “Physics”

  8. Dolly.

    Hi I’m dolly..
    Jo bhi lok ye app download krk pdhai krr kre hai vo unka future boht hi jyada bright hone vala hai.. because baat free off cost prhne ki nahi hai,baat kaise study krne ki hai…fhir chahe vo jaise bhi ho…main sbko bss itna hi kehna chahti hu ke boh ache se iss app ka use kro and kisi bhi competitive exam ke liye ye app boht acha hai…and please comment jrur chod ke jna .. thank you

  10. lista escape roomów

    hey there and thank you for your info – I’ve certainly picked up something
    new from right here. I did however expertise several technical points using this website, as I experienced
    to reload the website lots of times previous to I could
    get it to load correctly. I had been wondering if your hosting is OK?
    Not that I am complaining, but sluggish loading instances times will very frequently affect your
    placement in google and can damage your high quality score if advertising and marketing
    with Adwords. Anyway I am adding this RSS to my e-mail and can look out for much more of your respective intriguing content.
    Make sure you update this again soon.. Escape rooms hub

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top