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According to law of calorimetry, which of the given relation is true?

Name the pollution as seen in figure..

What causes the capillary action?

A ray through the centre of curvature hitting the spherical mirror makes an angle ofwith the normal.

The same size image in all positions of the object is obtained by a

State whether the following statements are true or false:

(a) Sound cannot travel in vacuum.

(b) The number of oscillations per second of a vibrating object is called its time-period.

(c) If the amplitude of vibrations is large, sound is feeble.

(d) The lower the frequency of vibration, the higher is the pitch.

(e) If the amplitude of vibrations is doubled, the loudness of sound also gets doubled.

(f) When the amplitude of vibrations is halved, the loudness of sound becomes one-fourth.

(g) Unwanted or unpleasant sound is termed as music.

(h) Noise pollution may cause partial hearing impairment.

Name one musical instrument each in which the sound is produced :

(a) by vibrating a stretched siring.

(b) by vibrating air enclosed in a tube.

(c) by vibrating a stretched membrane

(d) by vibrating metal plates.

The process of purification of an impure metal is like :
(a) electroplating a metal on the same type of metal
(b) electroplating a metal on another type of metal
(c) producing a chemical compound by electrolysis
(d) decomposing a chemical compound by electrolysis.

Lightning occurs due to:

Explain why, if a stone held in our hand is released, it falls towards the earth.

The resistance between a lightning protection system and earth should be:

What does magnitude of a force represent?

The biggest planet of the solar system is:

(a) Mars

(b) Saturn

(c) Mercury

(d) Jupiter

Find the density of a wooden cube whose side is $12cm$ long and has a mass of $3.5kg$.

An iron ring is heated uniformly. Which of the following will be affected?

Which of the following equipment works on similar principle as human eye?

Calculate the speed sound for a frequency of 520 Hz and a wavelength 220 cm.

What is the difference between a meteor and a meteorite ?

Three points which determines the loudness of sound?

Mohan wants a silver coating for his carbon magic stick. For accomplishing this he takes a battery, a container half filled with silver nitrate solution, a silver plate and his magic stick. But he is confused in connecting the battery terminals either to silver plate or magic stick. He should connect

A light ray is incident on a flat surface, making an angle of 20° with the surface. What is the angle of incidence and angle of reflection respectively?

The brightest star in the night sky called sirius is located close to one of the following constellations. This constellation is:

(a) Great Bear

(b) Leo Major

(c) Cassiopeia

(d) Orion

Why does ball get bounce even when gravitational force is acting on it

How can you reduce the drag on something moving on:

(a) air

(b)water

The odometer of a car reads $3000\text{km}$ at the start of a trip and $3400\text{km}$ at the end of the trip. If the trip took $8\text{hr}$, calculate the average speed of the car in ${\text{m min}}^{-1}$.

Use the following information to answer the next question.

The given figure shows the reflection of three rays from a reflecting surface.

On observing the incident and reflected rays, it can be inferred that

Dentists use concave mirrors for examining teeth. When the mirror is placed close to teeth, the image formed is:

Identify the correct pairs of labelled parts of Cavendish's experimental setup.

What is meant by saying that the friction is a self-adusting force

I take an empty can and pierce a hole near it's bottom and cover the hole with an adhesive tape. Now I fill the can with water and stretch a balloon over the mouth of the can. Now I take the can over the sink and take off the tape covering the hole. The balloon caves in. Why does this happen?

Name two ways of changing liquid state to the vapour state and distinguish them.

How is M.C.B. superior to the fuse wire?

In which case will there be more frictional force- i) When starting to move a heavy wooden block of wood or ii) when the heavy block is in motion. [1 MARK]

Observe the given figure. Which part of human eye senses the images of various objects in the surroundings?

When a parachute is opened, it moves very slowly because of

Define force?

Describe an experiment to show that liquid pressure depends on the density of the liquid.

The loudness of sound depends upon _______.