Which form of energy is transferred when a ice cube at 0’C is placed in a beaker of water at 50’C 1 chemical
2 electrical
3 nuclear
4 thermal

4. thermal

Explanation:

When there is a difference in the temperatures of an object and the environment, heat is transferred. The transfer of heat is the form of transfer of thermal energy. The energy from the hotter object gets transferred to the cooler object. This is the process of transfer of heat. In this process, the object that is hotter is likely to get cool and vice-versa.  

As per the given statement, when an ice cube is placed in a weaker of water, the transfer of thermal energy will take place. Here, ice cube is the cooler object and the beaker of water is hotter.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.