When an object is placed 10 cm in front of a convex lens, the image form is real, enlarged and inverted.
What is a possible value for the focal length of this convex lens?

A. 4cm
B. 8cm
C. 10cm
D. 12cm

The answer says B. 8cm but why?? please explain to me clearly

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

Which is not true about oxygen-17 and oxygen-18?

The ultracentrifuge is an important tool for separating and analyzing proteins. because of the enormous centripetal accelerations, the centrifuge must be carefully balanced, with each sample matched by a sample of identical mass on the opposite side. any difference in the masses of opposing samples creates a net force on the shaft of the rotor, potentially leading to a catastrophic failure of the apparatus. suppose a scientist makes a slight error in sample preparation and one sample has a mass 10 mg larger than the opposing sample. if the samples are 12 cm from the axis of the rotor and the ultracentrifuge spins at 70,000 rpm, what is the magnitude of the net force on the rotor due to the unbalanced samples? ( be thorough on your answer)