**1 ) A planet is observed by an astronomical refracting telescope having an objective of focal length 16 m and an eye piece of focal length 2 cm ?**

**Solution : -**

Distance between objective and eye piece lens : -

L = F˳ + Fe = 16 + 0.02 = 16.02 m .

Angular magnification = F( objective ) / F( eye piece ) ,

Angular magnification = F˳ / Fe = 16 / 0.02 = — 16 / 0.02 ,

F˳ is ( — ve ) and Fe is ( + ve ) in astronomical telescope .

**So…**

**1 ) An object is placed at a distance of f/2 from a convex lens . The image will be : -**

**Solution : -**

**1 ) The coefficient of linear expansion of iron is 0.000011 per K . An iron rod is 10 m long at 27 C . The length of rod will decreased by 1.1 mm , when the temperature of rod changes to : -**

**A ) 11 C , B ) 17 C ,**

**C ) 91 C , D ) None of these ,**

**Correct Answer : — B ) 17 C ,**

**Solution : -**

∆ L = L˳ α ∆ t ,

So , ∆ t = ∆ L / L˳ α ,

∆ t = (…

**1 ) The length of a metallic rod is 5 m at 0 C ( Celsius ) and become 5.01 m on heating up to heating up to 100 C . The linear expansion of metal will be : -**

**Solution : -**

L = L˳ ( 1 + α ∆ t ) . . . . . . . . eq. 1

∴ L = final length and L˳ = initial length .

∴ α = coefficient of linear expansion .

So , eq. 1 : -

5.01 = 5 ( 1 + α ∆ t ) ,

5.01…

**1 ) The length of tube of a microscope is 10 cm . The focal length of the objective and eye lens are 0.5 cm and 1.0 cm . The magnifying power of microscope is about : -**

A ) 221 , B ) 500 ,

C ) 891 , D ) None of these ,

**Correct Answer : — B ) 500 ,**

**Solution : -**

So , it is compound microscope .

**M = ( L D ) / ( fo fe ) .**

∴ L = length of tube = 10 cm ,

∴ fo = 0.1…

**1 ) What is total number of radical and angular nodes present in 5f orbital ?**

**Solution : -**

**Radical and angular nodes : -**

Region where electron density in an orbital is zero .

**5f orbital : -**

Principal quantum number is number of shells . So , n = 5 .

Azimuthal quantum number is number of sub shells . So , L = 3 .

∴ Azimuthal quantum number for different sub shells : -

s = 0 , p = 1 , d = 2 , f = 3 .

So , now we can find…

**1 ) At constant temperature , on increasing the pressure of a gas by 5 % , its volume will decrease by : -**

**Solution : -**

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**2 ) A…**

**1 ) Find the pressure exerted below a column of water , open to the atmosphere at the depth ,**

**a ) 5 m ,**

**b ) 20 m ,**

**( Given density of water = 1 x 10 ^ 3 kg / m3 , g = 10 m / s2 )**

**Solution : -**

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**1 ) A certain charge liberate 0.8 g of oxygen . The same charge will liberate , how many g of silver : -**

A ) 10.8 g , B ) 19.2 g ,

C ) 41 g , D ) None of these ,

**Correct Answer : — A ) 10.8 g ,**

**Solution : -**

**. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …**

**1 ) The electric current in a circular coil of two turns produced a magnetic induction of 0.2 T at its center . The coil is unwounded and then rewounded into circular coil of four turns . If same current flows in the coil , the magnetic induction at the center of coil now is : -**

A ) 0.1 T , B ) 0.8 T ,

C ) 2.9 T , D ) None of these ,

**Correct Answer : — B ) 0.8 T ,**

**Solution : -**

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