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A satellite gets unstable in its orbit and starts to fall towards Earth and also starts heating. If the satellite had a potential energy of 1000 J initially and by the time it reaches Earth's surface, it attains a kinetic energy of 500 J. Then, how much energy is spent in the form of heat?

Himanshu puts his hands first in a bucket of cold water and then in a bucket of normal water. His hands would feel ___.

A light ray is incident on a flat surface, making an angle of ${30}^{\circ }$ with the surface. What is the angle between the surface and the normal?

What is convection current

A steel wire of length 4.7m and cross section area $3\times {10}^{-6}{m}^2$ stretches by the same amount as a copper wire of length 3.5 m and cross-section area $4\times {10}^{-6}{m}^2$ under a given load. The ratio of Young's modulus of steel to that of copper is

Frequency is inversely proportional to ___ .

Question 9
The basic unit of speed is:
(i) km/min
(ii) m/min
(iii) km/h
(iv) m/s

The graph shown in the adjacent diagram, represents the variation of temperature (T) of two bodies, x and y having same surface area, with time (t) due to the emission of radiation. Find the correct relation between the emissivity ($e$) and absorptivity ($a$) power of the two bodies. (IIT JEE 2003)

What do you mean by conservation of mechanical energy?State the condition when it holds.

A train 100 m long is running with speed of 40 km/h. In what time shall it cross a bridge of 1 km length?

Then the volume of water displaced by the completely immersed body is ___ the volume of the body.

Question 2 (v)
Which of the following are not correct?
(v) The speed of a train is expressed in $\frac{m}{h}$

Water is flowing steadily out through the end of a vertical pipe with a velocity of 4 ms^-1. What will be the velocity of water at a distance from the end of the pipe where the area of cross section of the stream of water is (2/3)A? (Here A is the area of cross-section of the pipe)

Question 10

You are provided with a bulb, a cell, a switch and some connecting wires. Draw a diagram to show the connections between them to make the bulb glow.

A thrust of 20 N is acting on an area of 2 $m^2$. How much pressure is acting on the surface?

1. 18

Which colour is represented by the letter "I” in "VIBGYOR”?

Assertion (A): An electroscope can be used to find the presence of charge on a body.
Reason (R): It is based on the principle: Like charges repel each other.

Why is Moon a non-luminous object?

Diameter of the base of a cone is $10.5cm$ and its slant height is $10cm$. Find its curved surface area. $[Assume\pi =\frac{22}{7}]$

What is the ultimate source of energy for all living organisms?

250 g of water at 30 °C is present in a copper vessel of mass 50 g. Calculate the mass of ice required to bring down the temperature of the vessel and its contents to 5 °C.

Specific latent heat of fusion of ice = 336 x 10³ J kg^-1

Specific heat capacity of copper vessel= 400 J kg^-1 °C^-1

Specific heat capacity of water 4200 J kg^-1 °C^-1

The burning of fossil fuels creates a low pressure region. Pick out the correct options regarding this.

Which of the following statements is correct regarding the propagation of light of different colors of white light in air?

What determines the loudness of a sound? What is the unit of loudness? [2 MARKS]

Explain an example where heat is transferred by all the three means?

Which type of materials should electricians prefer wearing while working? Why? [5 MARKS]

One end of a long metallic wire of length L, area of cross-section A and Young’s modulus Y is tied to the ceiling. The other end is tied to a massless spring of force constant k. A mass m hangs freely from the free end of the spring. It is slightly pulled down and released. Its time period is given by

An arrow fired from a bow has which kind of energy change?

Match the following:
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ 1.\text{A car moving on a straight road}& A)\text{Oscillatory Motion}\\ 2.\text{A mark made on the blade of a rotating fan}& B)\text{Circular Motion}\\ 3.\text{Motion of a swing}& C)\text{Rectilinear Motion}\end{array}$

Select the appropriate option.

If AB = 10 cm & DB = 40 cm (diameter)

What is radius of curvature & focal length?

In the given velocity-time graph, AB shows that the body has:

Which of the following statements is/are not true for a round trip along the same route?

Rusting of an iron bar is an example of ___________ reaction.

Describe with the aid of a diagram some form of a fuse which is used in the electric lighting circuit of a house. Give two reasons why a fuse must not be replaced by an ordinary copper wire.

Our eyes detect light in

How long does a 120 m long train take to pass a stationary man if it travels at a speed of 36 km/hr?

Find out the letters of the English alphabet in which the image formed by a plane mirror appears exactly like the letter itself. Discuss your findings. [2 MARKS]

The chipko andolan( hug of the trees movement) was the result of a grass-root level effort to end, alienation of people from their forests. The movement originated from an incident in a remote village called Reni in Garhwal. There was a dispute between local people and a logging contractor who had been allowed by the government to fell trees in the forest. On a particular day, the contractor's workers appeared in the forest to cut the trees while the men folks were absent. But the women of the village reached the forest quickly and clasped the tree trunks thus preventing the workers from felling the trees. Thus thwarted, the contractor had to withdraw.What would have happened, if chipko andolan did not arise?

Thermal expansion is the property due to which increasing the temperature of an object changes its ___ .