Question: Ultrasonic waves are those sound waves having frequency
1. between 20 hertz and 1000 hertz
2. between 1000 hertz and 20000 hertz
3. less than 20 hertz
4. more than 20 kilohertz
Answer: 4
Question: The best colours for a Sun umbrella will be –
1. white on top and black on inside
2. red on top and black on inside
3. black on top and white on inside
4. black on top and red on inside
Answer: 1
Question: Before X-ray examination (coloured X-ray) of the stomach, patients are given suitable salt of barium because –
1. barium is a good absorber of X-rays and helps stomach to appear clearly
2. barium salts are white in colour and this helps stomach to appear clearly
3. barium allows X-rays to pass through the stomach
4. barium salts are easily available
Answer: 1
Question: In SONAR, we use –
1. radio waves
2. audible sound waves
3. infrasonic waves
4. ultrasonic waves
Answer: 4
Question: A liquid is kept in a regular cylindrical vessel up to a certain height. If this vessel is replaced by another cylindrical vessel having half the area of cross-section of the bottom, the pressure on the bottom will –
1. be increased to twice the earlier pressure
2. be reduced to one-fourth the earlier pressure
3. remain unaffected
4. be reduced to half the earlier pressure
Answer: 1
Question: The time period of a simple pendulum having a spherical wooden bob is 2 second. If the bob is replaced by a metallic one twice as heavy, the time period will be –
1. more than 2 second
2. 1 second
3. 2 second
4. less than 1 second
Answer: 3
Question: Which one among the following statements about an atom is not correct?
1. Atoms are the basic units from which molecules and ions are formed
2. Atoms always combine to form molecules
3. Atoms aggregate in large numbers to form the matter that we can see, feel and touch
4. Atoms are always neutral in nature
Answer: 3
Question: The working principle of a washing machine is –
1. Dialysis
2. Centrifugation
3. Reverse osmosis
4. Diffusion
Answer: 2
Question: A spherical ball made of steel when dropped in mercury container will
1. sink in mercury
2. will be on the surface of mercury
3. will be partly immersed in mercury
4. will dissolve in mercury
Answer: 3
Question: The sounds having a frequency of 20 Hertz to 20,000 Hertz are known as
1. Ultrasonics
2. Audible sounds
3. Infrasonics
4. Megasonics
Answer: 2
Question: Pure water is bad conductor of electricity because it is
1. not volatile
2. feebly ionized
3. a non-polar solvent
4. a very good solvent
Answer: 2
Question: The metals commonly used for electroplating are
1. Gold, Sodium & Chromium
2. Chromium, Copper & Nickel
3. Nickel, Lead & Chromium
4. Gold, Sodium & Potassium
Answer: 2