Can we use iPhone adaptor with iPad?

The iPhone Charger will charge the iPad... But... ever so slowly...

iPad Charging

"The fastest way to charge your iPad is with the included USB Power Adapter.

iPad will also charge, although more slowly, when attached to a computer with a high-power USB port (many recent Mac computers) or with an iPhone Power Adapter.

When attached to a computer via a standard USB port (most PCs or older Mac computers) iPad will charge, but only when it's in sleep mode.

Make sure your computer is on while charging iPad via USB. If iPad is connected to a computer that’s turned off or is in sleep or standby mode, the iPad battery will continue to drain."

Leg@las wrote:

Is it possible to use iPhone adaptor with iPad?

The answer to your question is yes. Just won't charge as fast. You do realize you can use your iPad charger with your phone, correct? If you have an iPad Mini, the charger is the same as the iPhone charger.