Open glass flask having a spherical shape of radius 2 cm, neck length of 10 cm and a diameter of 1 cm heated to a temperature t1, and then immersed completely in the water upside down. While cooling the flask water entered into the neck. When the bulb has taken 13 ° C, it was lifted out of the water, without turning, so that the spherical part was over the water, and the neck - partially submerged in the water. When the water levels in the neck and out lined, remained under water half the bottle. Is the temperature t1, which has been heated to the bulb?

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