Câu 27: Hai dây sắt, dây 1 có đường kính và chiều dài gấp đôi dây 2. Kết luận nào sau đây là đúng? A. S1< S2 B. R1 = 4 R2 C. R1 = ½ R2 D. R1 = R2 Câu 28: Một dây Nikelin ρ=0,40.10- 6Ωm, dài 10m, tiết diện 0,1 mm2sẽ có điện trở là: A. 10Ω B. 20Ω C. 30Ω D. 40Ω h Câu 29: Một dây Nikelin ρ=0,40.10- 6Ωm, dài 10m, tiết diện 0,1 mm2 mắc vào hai điểm có U=12V thì dòng điện qua nó có cường độ là: A. 0,3A B. 0,15A C. 0,10A D. 0,05A

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Many years ago when the summers seemed longer and life was (1).................... complicated. We had rented a cottage by a river in the beach of the country where were going to (2)....................... three weeks’ holiday . There were four of us : me (age 9 ) mum and dad and mum’s (3).................... , auntie June, oh, I mustn’t forget to (4) ................ Spot, our little dog . I was allowed to go off by (5)........... all day , (6).................. that I promised to be careful and took spot with me for (7) ............................... One day I was out fishing with spot when we heard a lot of shouting in the (8)......followed by a scream and a splash , I was a bit (9).....so I called spot and we both hide (10)...a bush where we could see but not be (11) ....After a few moments a straw hat came floating down the river , followed by a oar , a picnic basket and (12).... oar . Then came the rowing boat itself , but it was floating (13) ....down ! A few second later my dad and Auntie June came running (14).... the river bank , both wet (15) ...Spot started (16).... so I came out of hiding and said hello . My dad got really angry with me for not (17) .....to catch the boat as it went past . Luckily , however , the boat and both the oars had been caught by an overhanging tree a little further downstream , but the hat or the picnic basket . So I had to let them (18)...... my sandwiches . Dad and auntie both made me (19).... not to tell mum what had happened in (20)....she was worried .