A copper ball of density `8.6 gcm^(-3), 1 cm` is diameter is immersed in oil of density `0.8 dcm^(-3)`. If the ball remiand suspended in oil in a uniform electric field of intensity `36000NC^(-1)` acting in upward direction, what is the charge on the ball ?A. `1.1 muC`B. `4.2 muC`C. `2.4 muC`D. `3.7mu C`

A copper ball of density `8.6 gcm^(-3), 1 cm` is diameter is immersed

1.	A copper ball of density `8.6 gcm^(-3), 1 cm` is diameter is immersed in oil of density `0.8 dcm^(-3)`. If the ball remiand suspended in oil in a uniform electric field of intensity `36000NC^(-1)` acting in upward direction, what is the charge on the ball ?A. `1.1 muC`B. `4.2 muC`C. `2.4 muC`D. `3.7mu C`
Answer» Correct Answer - a Apparent weight of the ball `=mg-upthrust` `=4/3pir^(3)(rho-sigma)g=(4)/(3)pixx(0.5)^(3)xx(8.6-0.8)xx980` `= 4,002 dyn e= 4.0024xx10^(-2)N` Let `q` be the charge on the ball. As the ball remiand suspended, `qE=` apparent weightl of the ball or `q=("apparent weight")/(E)= (4.0024xx10^(-2))/(36,000)` `1.11xx10^(-6)C`

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