Which of the following brushes can be used for high values of current

1.	Which of the following brushes can be used for high values of current density ?
A.	Metal graphite brushes
B.	Hard carbon brushes
C.	Electro-graphitic brushes
D.	Natural graphite brushes
Answer» B. Hard carbon brushes

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Which of the following brushes can be used for high values of current density ?

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