If the radius of a cylinder is doubled and its curved surface area is not changed, the height must be

Explanation

True
Let the radius of a cylinder be r and height be h.
Curbved surface area of a cylinder `= 2pirh`
Again, let it the radius of a cylinder be r = 2r and height be H.
Curved surface of a cylinder is not charged, therefore .
` 2 pi rh = 2 pi (2r) xxH`
`rArr " "2pirh = 4pirh `
`rArr " " H= (2pirh)/(4pir)rArr H =(h)/(2)`
Hence, the height must be halved.