296. Consider the following elements
     1. cobalt
     2. phosphorous
     3. Zinc
     Which of the above elements are required for the maintaining healthy human body ?

1. 1. 1 and 2

   
   
   

   2. 2 and 3

   
   
   

   3. 1 and 3

   
   
   

   4. 1, 2 and 3

   
   
   

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   NA

   Correct Option: D

   NA

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297. The percentage of silver in german silver, is

1. 1. 0%

   
   
   

   2. 10%

   
   
   

   3. 2.5%

   
   
   

   4. 4.5%

   
   
   

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   NA

   Correct Option: A

   NA

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298. Which of the following alloys contains Cu and Zn ?

1. 1. Bell metal

   
   
   

   2. Aluminium bronze

   
   
   

   3. Brass

   
   
   

   4. Bronze

   
   
   

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   NA

   Correct Option: C

   NA

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299. Bell metal is an alloy of

1. 1. Cu + Sn

   
   
   

   2. Cu + Zn

   
   
   

   3. Cu + Ni

   
   
   

   4. Cu + Pb

   
   
   

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   NA

   Correct Option: A

   NA

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300. The outer electronic configuration of copper is

1. 1. 3d⁹ 4s²

   
   
   

   2. 3d¹⁰ 4s¹

   
   
   

   3. 3d¹⁰ 4s⁰

   
   
   

   4. 3d¹⁰ 4s²

   
   
   

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   NA

   Correct Option: B

   NA

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