# Induction cooker questions **URL:** \ **Category:** Factual Questions\ **Created:** [May 13, 2013, 4:29am UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211 "2013-05-13T04:29:13Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Duke\_of\_York](https://avatars.discourse-cdn.com/v4/letter/d/f6c823/32.png) [@Duke\_of\_York](https://boards.straightdope.com/u/Duke_of_York)\ **Post date:** [May 13, 2013, 4:29am UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/1 "2013-05-13T04:29:13Z")
Would an induction cooker damage such things as watches, mobile phones or other sensitive objects? I read somewhere that you should be careful with heart pacemakers, is that true? Plus, how far does the magnet field emit from the hotplate? ---
**Author:** ![Blue\_Mood](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@Blue\_Mood](https://boards.straightdope.com/u/Blue_Mood)\ **Post date:** [May 13, 2013, 10:08am UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/2 "2013-05-13T10:08:01Z")
The manual for mine says that they should not be used by people with pacemakers. We’ve never had a problem with watches or mobile phones (though I wouldn’t leave my credit cards on them). The magnets are direct - it only works if the pan is touching the field. Actually, I can feel it switch on when the pan is nearly touching - maybe a couple of millimeters away. I love my induction hob inordinately. It is my favourite possession. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [May 13, 2013, 1:12pm UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/3 "2013-05-13T13:12:54Z")
hang a paper clip (or part of one) from a thread. see how far away it has an effect. or use a compass. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [May 13, 2013, 1:17pm UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/4 "2013-05-13T13:17:21Z")
> [@Blue\_Mood](#): > > … > I love my induction hob inordinately. It is my favourite possession. 🙂 ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [May 13, 2013, 1:46pm UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/5 "2013-05-13T13:46:37Z")
> [@johnpost](#): > > hang a paper clip (or part of one) from a thread. see how far away it has an effect. > > or use a compass. The coils only power up when they sense a magnetic pan on them. I don’t think small pieces of iron will activate them. (like how motorbikes can’t trigger traffic signals) ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [May 13, 2013, 2:28pm UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/6 "2013-05-13T14:28:11Z")
Back in February I toured a factory that makes optical fiber. They use very high power induction heaters. I was warned not to get very near. I never got closer than 10 feet or so. When I got back to my hotel, the RFID key for my room no longer worked. It could not be reprogramed…it was dead. My cell phone was fine, though. An RFID tag is specifically designed to extract energy from RF fields, so a strong one might well overwhelm it. Of course, standard warnings about anecdotal evidence apply. ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [May 13, 2013, 2:32pm UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/7 "2013-05-13T14:32:56Z")
How do these induction hot plates compare to a typical resistive plate? The magnetic coupling must be somewhat weak. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [May 13, 2013, 3:05pm UTC](https://boards.straightdope.com/t/induction-cooker-questions/658211/8 "2013-05-13T15:05:29Z")
An induction hotplate will boil water about six zillion times faster than a regular one. The magnetic field is not for coupling the pan to the plate, it’s for heating up the pan via induction instead of the much slower process of conduction.