In a store, I found small multimeters of 5k ohm/V and 10 kohm /V. Which one is the best?
The ohm/volt specification indicates the multimeter's sensitivity. In the case of digital multimeters, simply input resistance is specified. So, if you want to buy an analog multimeter, the higher the ohm/volt value, the more sensitive the instrument is. The smaller the change it will cause in the circuit when measuring a voltage. It will load less the circuit under test.