81) What does the rusting of iron nail?
Increases its weight
82) Which is useful in the detection of landmines?
83) Which instrument used to measure the force and velocity of the wind?
84) What is most suitable for the core of an electromagnet?
85) A convex mirror makes a good rear-view mirror for a car. Why?
It forms erect, reduced images
86) For the measurement of temperature of the order of 400°C, what will we prefer?
87) If the current in the core decreases, what will the strength of the magnetic field be?
88) What is the commonly used unit for measuring the speed of data transmission?
Bits per second
89) The change in temperature of a body is 50°C. What is the change on Kelvin scale?
90) What is the amount of actual water vapour of air?
91) How is Missile ‘Astra’?
A air to air missile
92) What is Electric field intensity at a point a hollow charged spherical conductor?
93) With which instrument can a sailor in a submarine see the objects on the surface of sea?
94) At absolute zero temperature, what will be the kinetic energy of the molecules?
95) Which is the instrument that measures air pressure?
96) By whom was the quantum theory first enunciated?
By Max Planck
97) If a proton of mass m is moving with velocity of light, how will its mass?
98) What is the working principle of Rocket?
Newton’s 3rd Law
99) Rice is cooked more quickly in a pressure cooker because?
water boils at Higher temperature.
100) Why the raindrops acquired the spherical shape?