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1. An object of mass 350gram and volume 50cm3 is dropped into a liquid of density 0.9 g/cm3. Will it float or sink?

2. Write electronic configuration for the following elements
i) Oxygen (Z=8) ii) Aluminum (Z=13)
3. State law of definite proportion with an example.
4. What is mass of hydrogen and oxygen in 36grams of water?
5. A Secretariat building is under construction in Amravati. Mr. Anish wanted to check whether cracks are present in the walls of the building. Suggest a method by which he can test.
6. An object of mass 20g is thrown up with a velocity of 30m/s. Find the Total Energy after t=2seconds.
7. If the volume of a musical instrument is increased, what character of sound is changed?
8. Find Kinetic energy of a car moving at a speed of 72kmph having a mass of 1000kg.


1 Answer is in the image ..

2. electronic configuration of ,
i)oxygen = 2,6
ii)Aluminium =2,8,3

3.law of constant proportion was introduced by PROUST . This law states that in a chemical compound elements combine in a small whole no. in ratio of fixed proportion by mass.
for example : In compound NH3 elements N and H are in the fixed ratio of 14:3

5.He must pass ultrasonic waves from the building walls of they pass undeflected then there is no crack present but if gets deflected then there is a crack present.

8.Velocity=72kmph =72*5/18=20 m/s


kinetic energy= 1/2mv^2
= 1/2*1000*400=200000j
= 200kj

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