Radioactivity — Physics STD 10 — Question

(a) What is a machine?
(b) State three functions of a machine.

A uniform metre rule of weight 10gf is pivoted at its 0 mark.

What moment of force depresses the rule?

Why do we use water as a cooling agent in the radiators of automobiles?

State the penetrating range of α, β and γ radiations.

(a) Explain how is land breeze caused.
(b) Why is the weather in coastal regions moderate?

Name the pulley which has no gain in mechanical advantage. Explain, why is such a pulley then used?

A wire stretched between two fixed supports, is plucked exactly in the middle and then released. It executes (neglect the resistance of the medium):

• Resonant vibrations

• natural vibrations

• Damped vibrations

• Forced vibrations

State Fleming's left hand rule.

(a) State two ways by which the magnetic field of a solenoid can be made stronger.
(b) What material is used for making the armature of an electric bell? Give a reason for using this material.