Physics miscellaneous


  1. One Kilowatt hour is equal to—









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    The energy 1 kilowatt-hour (kWh) is 3600000 joules or 3.6 mega joule. In physics, energy is an indirectly observed quantity that is often understood as the ability of a physical system to do work on other physical systems. However, this must be understood as an overly simplified definition, as the laws of thermodynamics demonstrate that not all energy can perform work.

    Correct Option: A

    The energy 1 kilowatt-hour (kWh) is 3600000 joules or 3.6 mega joule. In physics, energy is an indirectly observed quantity that is often understood as the ability of a physical system to do work on other physical systems. However, this must be understood as an overly simplified definition, as the laws of thermodynamics demonstrate that not all energy can perform work.


  1. The plastic material commonly used for making gear wheels is









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    Popular materials for plastic gears are acetal resins such as DELRIN, Duracon M90; nylon resins such as ZYTEL, NYLATRON, MC901 and acetal copolymers such as CELCON. The physical and mechanical properties of these materials vary with regard to strength, rigidity, dimensional stability, lubrication requirements, moisture absorption, etc .A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, torque, and direction of a power source.

    Correct Option: B

    Popular materials for plastic gears are acetal resins such as DELRIN, Duracon M90; nylon resins such as ZYTEL, NYLATRON, MC901 and acetal copolymers such as CELCON. The physical and mechanical properties of these materials vary with regard to strength, rigidity, dimensional stability, lubrication requirements, moisture absorption, etc .A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, torque, and direction of a power source.



  1. Which of the following statements is true when we see ‘rainbow’ ?









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    We see rainbows because of the geometry of raindrops. When the sun shines from behind us into the rain, incident rays of light enter the drop and are refracted inwards. They are reflected from the back surface of the raindrop, and refracted again as they exit the raindrop and return to our eyes. A rainbow is an optical and meteorological phenomenon that is caused by reflection of light in water droplets in the Earth’s atmosphere, resulting in a spectrum of light appearing in the sky.

    Correct Option: B

    We see rainbows because of the geometry of raindrops. When the sun shines from behind us into the rain, incident rays of light enter the drop and are refracted inwards. They are reflected from the back surface of the raindrop, and refracted again as they exit the raindrop and return to our eyes. A rainbow is an optical and meteorological phenomenon that is caused by reflection of light in water droplets in the Earth’s atmosphere, resulting in a spectrum of light appearing in the sky.


  1. How much calorie of energy is released by a boiled egg ?









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    77-78 calories are released in a large size boiled egg. Boiled eggs are eggs (typically chicken eggs) cooked by immersion in boiling water with their shells unbroken.

    Correct Option: D

    77-78 calories are released in a large size boiled egg. Boiled eggs are eggs (typically chicken eggs) cooked by immersion in boiling water with their shells unbroken.



  1. The splitting of different colours of light in a prism is :









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    The refractive index of many materials (such as glass) varies with the wavelength or colour of the light used, a phenomenon known as dispersion. This causes light of different colours to be refracted differently and to leave the prism at different angles, creating an effect similar to a rainbow. In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency. Media having such a property are termed dispersive media. Dispersion is sometimes called chromatic dispersion to emphasize its wave length dependent nature, or group-velocity dispersion (GVD) to emphasize the role of the group.

    Correct Option: B

    The refractive index of many materials (such as glass) varies with the wavelength or colour of the light used, a phenomenon known as dispersion. This causes light of different colours to be refracted differently and to leave the prism at different angles, creating an effect similar to a rainbow. In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency. Media having such a property are termed dispersive media. Dispersion is sometimes called chromatic dispersion to emphasize its wave length dependent nature, or group-velocity dispersion (GVD) to emphasize the role of the group.