Important 500 Questions Of Physics part-4
- “The physical and chemical properties of elements are periodic functions of their atomic weights.” Who propounded this law – Mendeleev
- 1 kilometer distance means – 1000m
- 1 Nautical Mile is equal to – 1.85Km
- 1 Fathom is equal to – 1.80 Km
- 1 bar is equal to – 105 Pa
- How many liters are there in 1 barrel – 159
- 1 mile is equal to – 1.61Km
- Inert elements are members of which group – Zero group
- A jet aircraft is flying in the air with a speed of Mach 2. When the speed of sound is 332 m/s then what is the speed of the aircraft – 664 m/s
- A biological method that uses ultrasonic sound – sonography
- One picogram is equal to – 10-12 g
- One micron is equal to – 1/1000 mm
- The elements of which group are called ‘coin metals’ – IB
- The fluctuation in frequency of a sound source is called – Doppler effect.
- Which element when mixed with iron forms steel which can resist high temperatures and which has high hardness and abrasion resistance – Chromium
- Which waves cannot propagate in vacuum – sound
- The chemical composition of rust is – Fe2O xH2O
- The weight of iron increases when it rusts.
- Important metals used in making rust-free iron are – Chromium
- When two loudspeakers play simultaneously at a place, the listener sitting at a particular place does not hear their sound. The reason for this is – interference
- When the army crosses the bridge, the soldiers are instructed not to walk out of step because there is a danger of the bridge collapsing due to the resonance of the sound produced by the feet.
- Doppler effect is related to sound
- Who did the first classification of elements – Dobereiner
- Due to which sound waves produce echo – Reflection
- Sound cannot pass through vacuum
- The speed of light in vacuum is – 3x 108 meters/second
- The frequency or intensity of the whistle of an approaching train increases, due to which phenomenon – Doppler effect
- Which is the second most abundant metal in the earth’s womb – Iron
- Resonance occurs due to waves – Reflection
- What is the value of Planck’s constant – 6.6 x10-34 joule second
- The minimum parameters required for setting up an aluminum enterprise in India are bauxite and availability of – Electricity.
- If va, vw, and vs are the velocity of sound in air, water, and steel respectively, then – va < vw < vs
- Radio tuning station is an example of – translation
- In which medium the speed of sound will be maximum at a temperature of about 200C – Iron
- Which metal is added to convert iron into steel – Nickel
- By what name are the elements kept in zero group known – Inactive elements
- Sonar is mostly used – by navigators.
- On which principle of sound does the stethoscope work – reflection
- To hear a clear echo, there should be a minimum distance of 30 meters between the reflecting surface and the sound source.
- We listen to programs from different stations by turning the knob of the radio. This is possible – due to resonance
- What is the instrument used for identifying and mapping sound waves called – Sonar
- Which shock wave does a supersonic aircraft produce? – Ultrasonic wave
- Echo sounding is used to measure the depth of the ocean.
- Two people cannot hear each other on the surface of the Moon because there is no atmosphere on the Moon.
- While shouting, a person always keeps the palm near the mouth, because in that case the sound energy will point in only one direction.
- Decibel unit is used for intensity of sound.
- Sound or noise pollution is measured in decibels.
- The speed of sound in air is 332 meters per second. If the pressure is doubled then the speed of sound will be – 332 m/second.
- What does sound travel fastest in – steel
- Thunder is heard long after the flash of lightning. The reason for this is – the speed of light is much greater than the speed of sound.
- The speed of sound in air is approximately – 330 m/s.
- The speed of sound is lowest in gas.
- What is the mass number of an element whose atom has two protons, two neutrons and two electrons? – 4
- The size of the nucleus is – 10-15 m
- Energy is created on the Sun – through nuclear fusion
- Which has negative charge – ß particle
- The difference between a nuclear reactor and an atomic bomb is that in a nuclear reactor the chain reaction is controlled.
- The alpha particle has two units of positive charge. Its mass is approximately equal to that of one atom of helium.
- At what temperature is the density of water maximum – at 40C
- Which part of the sun’s radiation heats the solar cooker – infrared rays
- Clothes keep us warm in winter because they prevent body heat from going out.
- When does water boil – The static vapor pressure of water is equal to the atmospheric pressure.
- By which method is heat transferred in liquids and gases? Convection
- A piece of ice is floating in a glass filled with water. When the piece melts completely, the level of water in the glass remains unchanged.
- What is the transmission of heat through molecular structure called – convection
- The boiling point of a liquid will increase as pressure increases.
- Steam burns hands more than boiling water because steam contains latent heat.
- When two pieces of ice are pressed together, the pieces stick together because – due to higher pressure, the melting point of ice decreases.
- Why are white clothes cooler than black clothes – they reflect whatever light reaches them
- Woolen clothes are warmer than cotton clothes because they are good insulators of heat.
- Bolometer is an instrument which measures- thermal radiation.
- The unit of measuring distance between stars is – light year
- Tachyon means particles moving faster than the speed of light.
- Einstein introduced the fourth dimension in physics.
- What is the instrument that measures the intensity of sun rays called – Actiometer
- How is the rotation per second of a flying disc measured – Stroboscope
- The function of thermostat in refrigerator is to maintain uniform temperature.
- Which concept is confirmed by the first law of thermodynamics – conservation of energy
- Cryogenic engines are used in rocket technology.
- Cryogenics is used in space travel, magnetic levitation and telemetry.
- Rice cooks quickly in a pressure cooker because – high pressure increases the boiling point of water.