A piece of polystyrene packaging material (density = 19 kgm−3) that has a mass of 0.25 kg is tethered to the bottom of a container of water (density = 1×103 kgm−3) with a piece of string. What is the tension in the string?​

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27