Q. When a ball bounces off the ground, which of the following changes suddenly? (Assume no loss of energy to the floor)
1) Its speed
2) Its momentum
3) Its kinetic energy
4) Its potential energy
Q. Which one of the following statements regarding Ohm's law is not correct?
1) Ohm's law is an assumption that current through a conductor is always directly proportional to the potential difference applied to it.
2) A conducting device obeys Ohm's law when the resistance of a device is independent of magnitude and polarity of applied potential difference.
3) A conducting material obeys Ohm's law when the resistance of material is independent of the magnitude and direction of applied electric field.
4) All homogeneous materials obey Ohm's law irrespective of whether the field is within range or strong.
Q. In which of the following phenomena do heat waves travel along straight line with the speed of light?
1) Thermal conduction
2) Thermal convection
3) Thermal radiation
4) Both, thermal conduction and radiation
Q. Let there be an object having some chemicals in it. It starts moving with a uniform velocity v and a chemical reaction starts happening. In this case, which of the following statement/s is/ are correct?
1. Chemical reactions happening in the system cannot change the velocity v of the center of mass of the object.
2. Chemical reactions happening in the system cannot change kinetic energy of the particles inside with respect to the center of mass of object.
Select the correct answer using the code given below -
1) 1 only
2) 2 only
3) Both 1 and 2
4) Neither 1 nor 2
Q. A thin disc and a thin ring, both have mass M and radius R. Both rotate about axes through their center of mass and are perpendicular to their surfaces at the same angular velocity. Which of the following is true?
1) The ring has higher kinetic energy
2) The disc has higher kinetic energy
3) The ring and the disc have the same kinetic energy
4) Kinetic energies of both the bodies are zero since they are not in linear motion
Q. First electro chemical cell was designed by -
1) Leclanche
2) Faraday
3) Galvanic
4) None of the above
Q. The velocity of sound in any gas depends upon -
1) Wavelength of sound only
2) Density and elasticity of gas
3) Intensity of sound waves only
4) Amplitude and frequency of sound
Q. It is difficult to cook at high altitude because -
1) There is less oxygen in the air
2) Due to fall in temperature, one has to give more heat
3) Due to decrease in atmospheric pressure the boiling point of water decreases
4) Of high moisture content at higher altitude
Q. The poorest conductor of heat among the following is -
1) copper
2) lead
3) mercury
4) zinc
Q. Which of the following does not change when light travels from one medium to another?
1) Velocity
2) Wavelength
3) Frequency
4) Refractive index
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