When my wife cooks spong cake it does not rise

Taras, Check the attached links,instruction and guides on cake baking strategies. Good luck .
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http://www.instantanswer.org/why-did-my-cake-not-rise_608.html

Reasons for Cakes Not to Rise LIVESTRONG COM

http://www.mumsnet.com/Talk/food_and_recipes/895729-Why-don-39-t-my-cakes-rise

Why Don My Cakes Rise High Enough

You can try Chicago metallic commercial jelly roll pans, they are perfect for making sponge cakes and much more.

Yeast will not rise using conventional microwave oven type energy. So, you can't have your microwave and eat it too ... (groan - sorry)

self rising flour uses baking powder as a leveling agent, so it rises as it is being heated in the cooking process, not like a yeast dough.
the following is taken from another site, I could not have said it any better.

Self-rising flour has an almost magical sound to it. And if you look at recipes that call for it, you'll see that they do not call for the addition of salt or leavening agents, though biscuits, cakes and breads made with seem to rise up just fine. The reason for this is that self-rising flour is actually nothing of the sort. It is flour that has a leavening agent - baking powder - and salt added to it during packaging. Since the ingredients are evenly distributed throughout the flour, you will get the same nice lift to your baked goods every time you use it. If you don't have self-rising flour and you have a recipe that calls for it, you can make your own by combining 1 cup all purpose flour with 1 tsp baking powder and 1/4 tsp salt. Similarly, if you only have self-rising flour, you can reduce the baking powder and salt called for in a recipe that uses standard all purpose flour.
Now that being said, it is also worth noting that there are several brands of self-rising flour that have a lower protein content than all purpose flour (11% protein). They are effectively cake flours (8% protein). Wheat protein, or gluten, is what gives baked goods much of their structure, but it can also cause a bread to be too dense or tough. White Lily and Presto are two examples of self-rising brands that use a low-protein cake flour as their base, and if a recipe calls for one of them, you should use cake flour in place of all purpose in the conversion given above.

It's possible that it's out of date and lost its leavening 'power'. Check the box directions to make sure your mix can be used for cupcakes. Also, not adding enough liquid might be the problem.

when i bake a chocolate sponge cake it rises well,when cooking the top becomes cracked like dry earth and when switched off it comes down about a third. with my previous oven baking thesame recipee for 30 years i never had a problem- please advise the reason for this problem

just squeeze the air out of the cake, position the circle on the bottom of the cake onto the circle in the oven, wave the wand over the heart or press the heart and it should rise in 5-30 seconds

the ideal temp in a fridge is +5C,no colder,or your veg will spoil.

Well, your temp seems about right, but you may need to experiment. A good thermometer helps in gauging temp, ovens are notoriously inaccurate. All oven are different, but it is usually recommended to go down 25 (15C) degrees from the recipe if you use convection. The type of pan you use has an effect. Glass needs to be 25 degrees less, and nonstick/dark pans brown faster than the insulated type. Make sure that you fully preheat as well, or the bottom may burn. Other than that, convection cook times are less if the bake time exceeds 15 or 20 minutes. Thanks for your question, sorry I can't give a more precise recommendation.

When you bake a cake the water is in the batter. The baking powder gives it a fizz, and the egg helps hold it in place once it rises.