Which state can a substance NOT be in if heat transfer through convection is occurring?

Photons with 605 THz frequency strike metal of 1.2eV work function. Calculate the maximum energy of photoelectrons and their velocity. What amount of energy is necessary to stop all photoelectrons? (Planck's constant. electron mass and charge are given)

A bomb of mass 34kg, at rest is detonated. The explosion splits the bomb into two pieces, one of mass 13kg, which is thrown to the left at a velocity of 28 m/s. What is the velocity of the second piece?

Sophia (mass 47Kg) is travelling to the right with a velocity of 7.2m/s and ​Neesha (mass 68Kg) is travelling to the left with a velocity 4.8m/s. When ​they meet, they hold hands and travel off together. Give their final ​velocity and direction

If a 30N force is applied to a stationary object of mass 10kg, at what speed will the object accelerate?