Newton's Corpuscular Theory of Light (न्यूटनचा पदार्थरूपी प्रकाशाचा सिद्धांत)

संस्कृतमध्ये एक प्रसिद्ध सुभाषित आहे,

                                अतिपरिचयदवज्ञा संततगमनादनादरो भवति ।

मलये भिल्लपुरंध्री चन्दनतरुकाष्ठमिंधनं कुरुते ॥

अगदी थोडक्यात सांगायचे तर अति परिचयाची एखाद्याचे मूल्य अथवा महत्व कमी होणे.   प्रकाशाचेही काही प्रमाणात असेच झालेले आहे. प्रकाश हि आपल्या दैनिंदिन जीवनातील   असामान्य प्रतिभा असलेली अतिसामान्य गोष्ट, अशीच अतिपरिचयेमुळे अवज्ञेस गेलेली.   प्रकाश म्हणजे काय असे कोणाला विचारले तर "अहो ते नाही का ते, 'सूर्य उगवला प्रकाश पडला आडवा डोंगर' आहे ना त्यातला प्रकाश " असे उत्तर मिळेलही . पण प्रकाश म्हणजे नेमके काय? प्रकाश कशापासून बनला आहे?  असे विचारले तर ??

                          

  

CBSE – AIPMT – 2011 de Broglie wavelength associated with electron

Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 km then the de-Broglie wavelength associated with the electrons would

(a) Increase by 4 times

(b) Increase by 2 times

(c) Decrease by 2 times

(d) Decrease by 4 times

JEE advance 2013 - A particle of mass 0.2 kg

A particle of mass 0.2 kg is moving in one dimension under a force that delivers a constant power 0.5 W to the particle. The initial speed (in m / s ) of the particle is zero, the speed ( in m / s ) after 5 sec is_ _ _ _ 

{ JEE advance 2013 }

The magnetic induction at center of coil

A Closely wound flat circular coil of 50 turns wound flat circular coil of 50 turns has a diameter of 10 cm carries a current of 4 ampere. Determine the magnetic induction at center of coil.

Solution:

In LCR series circuit, an alternating e.m.f. ‘ e ’ and current ‘ i ’ is given by equation e = 100 sin ( 100 t ) and i = 100 sin [ 100 t + (π/3) ] mA The average power dissipated in the circuit will be _ _ _ _ _ _ _ _ _ ( MHT - CET 2014 )

a ) 100 W              

b ) 10 W        

c ) 5 W                  

d ) 2.5 W

What is the force between two small charged spheres having charges of 2 × 10–7C and 3 × 10–7C placed 30 cm apart in air?

Solution :

Given :

a)      q ₁ = 2 × 10 ^{– 7} C

b)      q ₂ = 3 × 10 ^{– 7} C

c)       r   = 30 cm = 30 X 10 ^{– 3} = 3 X 10 ^{– 2}

d)      ε ₀ = 8.854 × 10 ^{– 12} C ² N ^–1 m^{– 2}

Formula : 

The force between two small charged spheres can be given as

F = [ 1 / ( 4 π ε₀ ) ] [ ( q₁ q₂) / ( r² ) ]

Therefore,

F = [ 1 / ( 4 X 3.14 X 8.854 × 10^–12 ) ] { ( 2 × 10^–7 X 3 × 10^–7) / [ ( 3 X 10^{– 2})² ] }

F = [ 1/(1.11 × 10^–10 ) ] [ ( 6 × 10^–14 ) / ( 9 X 10 ^–4 ) ]

F = [ 9 X 10 ⁹ ) ] [ ( 6 × 10^–10 ) / ( 9 ) ]

F = 60 N

The force between two small charged spheres having charges of 2 × 10^–7C and 3 × 10^–7C placed 30 cm apart in air is 60 newton 

The angle of minimum deviation of a glass prism is π – 2 A , where A is angle of prism. The angle of prism is _ _ _ _ _ _ _ _ _ _ _ _ .

a )      2 tan μ

    b )      2 tan^-1 μ   

    c )       2 cot^-1 μ

    d )      2 cot μ